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class="vector-toc-list"> <li id="toc-Bedded_chert" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Bedded_chert"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1</span> <span>Bedded chert</span> </div> </a> <ul id="toc-Bedded_chert-sublist" class="vector-toc-list"> <li id="toc-Subvarieties" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Subvarieties"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1.1</span> <span>Subvarieties</span> </div> </a> <ul id="toc-Subvarieties-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Nodular_chert" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Nodular_chert"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.2</span> <span>Nodular chert</span> </div> </a> <ul id="toc-Nodular_chert-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Other_occurrences" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other_occurrences"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.3</span> <span>Other occurrences</span> </div> </a> <ul id="toc-Other_occurrences-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Fossils" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Fossils"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Fossils</span> </div> </a> <ul id="toc-Fossils-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Prehistoric_and_historic_uses" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Prehistoric_and_historic_uses"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Prehistoric and historic uses</span> </div> </a> <button aria-controls="toc-Prehistoric_and_historic_uses-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Prehistoric and historic uses subsection</span> </button> <ul id="toc-Prehistoric_and_historic_uses-sublist" class="vector-toc-list"> <li id="toc-Tools" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Tools"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Tools</span> </div> </a> <ul id="toc-Tools-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Construction" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Construction"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Construction</span> </div> </a> <ul id="toc-Construction-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Varieties" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Varieties"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Varieties</span> </div> </a> <ul id="toc-Varieties-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>External links</span> </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet 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Available in 26 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-26" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">26 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%B5%D8%AE%D8%B1_%D8%B5%D9%88%D8%A7%D9%86%D9%8A" title="صخر صواني – Arabic" lang="ar" hreflang="ar" data-title="صخر صواني" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Chert" title="Chert – Catalan" lang="ca" hreflang="ca" data-title="Chert" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Rohovec" title="Rohovec – Czech" lang="cs" hreflang="cs" data-title="Rohovec" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Chert_(Gestein)" title="Chert (Gestein) – German" lang="de" hreflang="de" data-title="Chert (Gestein)" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Chert_(roca)" title="Chert (roca) – Spanish" lang="es" hreflang="es" data-title="Chert (roca)" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%DA%86%D8%B1%D8%AA_(%D8%B3%D9%86%DA%AF)" title="چرت (سنگ) – Persian" lang="fa" hreflang="fa" data-title="چرت (سنگ)" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Chaille" title="Chaille – French" lang="fr" hreflang="fr" data-title="Chaille" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/Seirt" title="Seirt – Irish" lang="ga" hreflang="ga" data-title="Seirt" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target"><span>Gaeilge</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EA%B0%81%EC%95%94" title="각암 – Korean" lang="ko" hreflang="ko" data-title="각암" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Chert" title="Chert – Indonesian" lang="id" hreflang="id" data-title="Chert" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/T%C5%B1zk%C5%91_(%C3%BCled%C3%A9kt%C3%ADpus)" title="Tűzkő (üledéktípus) – Hungarian" lang="hu" hreflang="hu" data-title="Tűzkő (üledéktípus)" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Hoornsteen" title="Hoornsteen – Dutch" lang="nl" hreflang="nl" data-title="Hoornsteen" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%83%81%E3%83%A3%E3%83%BC%E3%83%88_(%E5%B2%A9%E7%9F%B3)" title="チャート (岩石) – Japanese" lang="ja" hreflang="ja" data-title="チャート (岩石)" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Chert" title="Chert – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Chert" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Chert" title="Chert – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Chert" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Czert" title="Czert – Polish" lang="pl" hreflang="pl" data-title="Czert" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Cherte" title="Cherte – Portuguese" lang="pt" hreflang="pt" data-title="Cherte" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Chert" title="Chert – Romanian" lang="ro" hreflang="ro" data-title="Chert" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9A%D1%80%D0%B5%D0%BC%D0%BD%D0%B8%D1%81%D1%82%D1%8B%D0%B9_%D1%81%D0%BB%D0%B0%D0%BD%D0%B5%D1%86" title="Кремнистый сланец – Russian" lang="ru" hreflang="ru" data-title="Кремнистый сланец" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Chert" title="Chert – Simple English" lang="en-simple" hreflang="en-simple" data-title="Chert" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%A0%D0%BE%D0%B6%D0%BD%D0%B0%D1%86" title="Рожнац – Serbian" lang="sr" hreflang="sr" data-title="Рожнац" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Hornsten" title="Hornsten – Swedish" lang="sv" hreflang="sv" data-title="Hornsten" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%AB%E0%B8%B4%E0%B8%99%E0%B9%80%E0%B8%8A%E0%B8%B4%E0%B8%A3%E0%B9%8C%E0%B8%95" title="หินเชิร์ต – Thai" lang="th" hreflang="th" data-title="หินเชิร์ต" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target"><span>ไทย</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/%C3%87%C3%B6rt" title="Çört – Turkish" lang="tr" hreflang="tr" data-title="Çört" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%A4%D0%BB%D1%96%D0%BD%D1%82_(%D0%B3%D1%96%D1%80%D1%81%D1%8C%D0%BA%D0%B0_%D0%BF%D0%BE%D1%80%D0%BE%D0%B4%D0%B0)" title="Флінт (гірська порода) – Ukrainian" lang="uk" hreflang="uk" data-title="Флінт (гірська порода)" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/Chert" title="Chert – Vietnamese" lang="vi" hreflang="vi" data-title="Chert" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q1070438#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li 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free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Hard, fine-grained sedimentary rock composed of cryptocrystalline silica</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">For the Spanish municipality, see <a href="/wiki/Xert" title="Xert">Xert</a>. For an evil spirit in Slavic folklore, see <a href="/wiki/Chort" title="Chort">Chort</a>.</div> <p class="mw-empty-elt"> </p> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox"><caption class="infobox-title">Chert</caption><tbody><tr><td colspan="2" class="infobox-subheader" style="background-color: #cddeff"><b><a href="/wiki/Sedimentary" class="mw-redirect" title="Sedimentary">Sedimentary rock</a></b></td></tr><tr><td colspan="2" class="infobox-image"><span class="mw-default-size" typeof="mw:File/Frameless"><a href="/wiki/File:ChertUSGOV.jpg" class="mw-file-description"><img alt="Chert hand sample" src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/ChertUSGOV.jpg/220px-ChertUSGOV.jpg" decoding="async" width="220" height="210" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1c/ChertUSGOV.jpg/330px-ChertUSGOV.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/1/1c/ChertUSGOV.jpg 2x" data-file-width="360" data-file-height="344" /></a></span><div class="infobox-caption">A hand sample of chert</div></td></tr><tr><th colspan="2" class="infobox-header" style="background-color: #ededed">Composition</th></tr><tr><td colspan="2" class="infobox-full-data"><a href="/wiki/Microcrystalline" title="Microcrystalline">Microcrystalline</a> or <a href="/wiki/Cryptocrystalline" title="Cryptocrystalline">cryptocrystalline</a> <a href="/wiki/Quartz" title="Quartz">quartz</a></td></tr></tbody></table> <p><b>Chert</b> (<span class="rt-commentedText nowrap"><span class="IPA nopopups noexcerpt" lang="en-fonipa"><a href="/wiki/Help:IPA/English" title="Help:IPA/English">/<span style="border-bottom:1px dotted"><span title="/tʃ/: 'ch' in 'China'">tʃ</span><span title="/ɜːr/: 'ur' in 'fur'">ɜːr</span><span title="'t' in 'tie'">t</span></span>/</a></span></span>) is a hard, fine-grained <a href="/wiki/Sedimentary_rock" title="Sedimentary rock">sedimentary rock</a> composed of <a href="/wiki/Microcrystalline" title="Microcrystalline">microcrystalline</a> or <a href="/wiki/Cryptocrystalline" title="Cryptocrystalline">cryptocrystalline</a> <a href="/wiki/Quartz" title="Quartz">quartz</a>,<sup id="cite_ref-Knauth1979_1-0" class="reference"><a href="#cite_note-Knauth1979-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> the mineral form of <a href="/wiki/Silicon_dioxide" title="Silicon dioxide">silicon dioxide</a> (SiO<sub>2</sub>).<sup id="cite_ref-:0_2-0" class="reference"><a href="#cite_note-:0-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> Chert is characteristically of biological origin, but may also occur inorganically as a <a href="/wiki/Precipitation_(chemistry)" title="Precipitation (chemistry)">chemical precipitate</a> or a <a href="/wiki/Diagenesis" title="Diagenesis">diagenetic</a> replacement, as in <a href="/wiki/Petrified_wood" title="Petrified wood">petrified wood</a>.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> </p><p>Chert is typically composed of the petrified remains of <a href="/wiki/Siliceous_ooze" title="Siliceous ooze">siliceous ooze</a>, the biogenic sediment that covers large areas of the deep ocean floor, and which contains the silicon skeletal remains of <a href="/wiki/Diatom" title="Diatom">diatoms</a>, <a href="/wiki/Dictyochales" title="Dictyochales">silicoflagellates</a>, and <a href="/wiki/Radiolaria" title="Radiolaria">radiolarians</a>.<sup id="cite_ref-boggs-2006-208-210_4-0" class="reference"><a href="#cite_note-boggs-2006-208-210-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Precambrian" title="Precambrian">Precambrian</a> cherts are notable for the presence of fossil <a href="/wiki/Cyanobacteria" title="Cyanobacteria">cyanobacteria</a>.<sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> In addition to <a href="/wiki/Micropaleontology" title="Micropaleontology">microfossils</a>,<sup id="cite_ref-boggs-2006-208-210_4-1" class="reference"><a href="#cite_note-boggs-2006-208-210-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> chert occasionally contains <a href="/wiki/Macrofossil" title="Macrofossil">macrofossils</a>.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> However, some chert is devoid of any fossils.<sup id="cite_ref-FOOTNOTEBoggs2006207_8-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p><p>Chert varies greatly in color, from white to black, but is most often found as gray, brown, grayish brown and light green to rusty red<sup id="cite_ref-roberts-etal-1990_9-0" class="reference"><a href="#cite_note-roberts-etal-1990-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-mitchell-1985_10-0" class="reference"><a href="#cite_note-mitchell-1985-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> and occasionally as dark green.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> Its color is an expression of trace elements present in the rock. Both red and green are most often related to traces of iron in its <a href="/wiki/Redox" title="Redox">oxidized and reduced</a> forms, respectively.<sup id="cite_ref-boggs-2006-208-210_4-2" class="reference"><a href="#cite_note-boggs-2006-208-210-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Description">Description</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=1" title="Edit section: Description"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Chert_beds_EverettPA.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Chert_beds_EverettPA.jpg/220px-Chert_beds_EverettPA.jpg" decoding="async" width="220" height="144" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/2/23/Chert_beds_EverettPA.jpg/330px-Chert_beds_EverettPA.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/2/23/Chert_beds_EverettPA.jpg/440px-Chert_beds_EverettPA.jpg 2x" data-file-width="1245" data-file-height="816" /></a><figcaption>Chert (dark bands) in the <a href="/wiki/Devonian" title="Devonian">Devonian</a> Corriganville-New Creek limestone, <a href="/wiki/Everett,_Pennsylvania" title="Everett, Pennsylvania">Everett, Pennsylvania</a></figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Folded_layers_of_bedded_chert_formation_in_Busuanga,_Palawan_02.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Folded_layers_of_bedded_chert_formation_in_Busuanga%2C_Palawan_02.jpg/220px-Folded_layers_of_bedded_chert_formation_in_Busuanga%2C_Palawan_02.jpg" decoding="async" width="220" height="391" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Folded_layers_of_bedded_chert_formation_in_Busuanga%2C_Palawan_02.jpg/330px-Folded_layers_of_bedded_chert_formation_in_Busuanga%2C_Palawan_02.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Folded_layers_of_bedded_chert_formation_in_Busuanga%2C_Palawan_02.jpg/440px-Folded_layers_of_bedded_chert_formation_in_Busuanga%2C_Palawan_02.jpg 2x" data-file-width="2604" data-file-height="4624" /></a><figcaption>Folded beds of chert comprising the Late Permian to Jurassic-aged Liminangcong Formation at <a href="/wiki/Busuanga,_Palawan" title="Busuanga, Palawan">Busuanga, Palawan</a>, Philippines</figcaption></figure> <p>In <a href="/wiki/Petrology" title="Petrology">petrology</a>, the term "chert" refers generally to all chemically precipitated <a href="/wiki/Sedimentary_rocks" class="mw-redirect" title="Sedimentary rocks">sedimentary rocks</a> composed primarily of <a href="/wiki/Microcrystalline" title="Microcrystalline">microcrystalline</a>, <a href="/wiki/Cryptocrystalline" title="Cryptocrystalline">cryptocrystalline</a> and microfibrous <a href="/wiki/Silica" class="mw-redirect" title="Silica">silica</a>.<sup id="cite_ref-Folk1980_13-0" class="reference"><a href="#cite_note-Folk1980-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> Most cherts are nearly pure silica, with less than 5% other minerals (mostly <a href="/wiki/Calcite" title="Calcite">calcite</a>, <a href="/wiki/Dolomite_(mineral)" title="Dolomite (mineral)">dolomite</a>, <a href="/wiki/Clay_minerals" class="mw-redirect" title="Clay minerals">clay minerals</a>, <a href="/wiki/Hematite" title="Hematite">hematite</a>, and organic matter.)<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> However, cherts range from very pure cherts with over 99% silica content to impure nodular cherts with less than 65% silica content. Aluminium is the most abundant minor element, followed by iron and <a href="/wiki/Manganese" title="Manganese">manganese</a> or <a href="/wiki/Potassium" title="Potassium">potassium</a>, <a href="/wiki/Sodium" title="Sodium">sodium</a>, and <a href="/wiki/Calcium" title="Calcium">calcium</a>.<sup id="cite_ref-FOOTNOTEBoggs2006207_8-1" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> Extracrystalline water (tiny <a href="/wiki/Inclusion_(mineral)" title="Inclusion (mineral)">inclusions</a> of water within and around the quartz grains) make up less than 1% of most cherts.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p>The <a href="/wiki/Folk_classification" title="Folk classification">Folk classification</a> divides chert into three <a href="/wiki/Texture_(geology)" title="Texture (geology)">textural</a> categories. Granular microquartz is the component of chert consisting of roughly equidimensional <a href="/wiki/Quartz" title="Quartz">quartz</a> grains, ranging in size from a fraction of a micron to 20 microns, but most typically 8 to 10 microns. <a href="/wiki/Chalcedony" title="Chalcedony">Chalcedony</a> is a microfibrous variety of quartz, consisting of radiating bundles of very thin crystals about 100 microns long. Megaquartz is composed of equidimensional grains over 20 microns in size.<sup id="cite_ref-Folk1980_13-1" class="reference"><a href="#cite_note-Folk1980-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-FOOTNOTEBoggs2006206–207_16-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006206–207-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> Most chert is microcrystalline quartz with minor chalcedony and sometimes <a href="/wiki/Opal" title="Opal">opal</a>, but cherts range from nearly pure opal to nearly pure quartz chert. However, little opal is over 60 million years old.<sup id="cite_ref-FOOTNOTEBoggs2006206–207_16-1" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006206–207-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> Opaline chert often contains visible fossils of <a href="/wiki/Diatoms" class="mw-redirect" title="Diatoms">diatoms</a>, <a href="/wiki/Radiolarians" class="mw-redirect" title="Radiolarians">radiolarians</a>, and <a href="/wiki/Glass_sponge" class="mw-redirect" title="Glass sponge">glass sponge</a> <a href="/wiki/Sponge_spicule" title="Sponge spicule">spicules</a>.<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980572_17-0" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980572-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> </p><p>Chert is found in settings as diverse as <a href="/wiki/Hot_spring" title="Hot spring">hot spring</a> deposits (<i><a href="/wiki/Siliceous_sinter" class="mw-redirect" title="Siliceous sinter">siliceous sinter</a></i>), <a href="/wiki/Banded_iron_formation" title="Banded iron formation">banded iron formation</a> (<i><a href="/wiki/Jaspilite" class="mw-redirect" title="Jaspilite">jaspilite</a></i>),<sup id="cite_ref-FOOTNOTEBoggs2006207_8-2" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> or <a href="/wiki/Alkaline_lake" class="mw-redirect" title="Alkaline lake">alkaline lakes</a>.<sup id="cite_ref-FOOTNOTEBlattTracy1996336–338_18-0" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996336–338-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> However, most chert is found either as <i>bedded chert</i> or as <i>nodular chert</i>.<sup id="cite_ref-FOOTNOTEBoggs2006207_8-3" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> Bedded chert is more common in <a href="/wiki/Precambrian" title="Precambrian">Precambrian</a> beds, but nodular chert became more common in the <a href="/wiki/Phanerozoic" title="Phanerozoic">Phanerozoic</a> as the total volume of chert in the rock record diminished.<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980575_19-0" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980575-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> Bedded chert is rare after the early <a href="/wiki/Mesozoic" title="Mesozoic">Mesozoic</a>.<sup id="cite_ref-FOOTNOTEBlattTracy1996339_20-0" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996339-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> Chert became moderately abundant during the <a href="/wiki/Devonian" title="Devonian">Devonian</a> and <a href="/wiki/Carboniferous" title="Carboniferous">Carboniferous</a> and again became moderately abundant from the <a href="/wiki/Jurassic" title="Jurassic">Jurassic</a> to the present.<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-0" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980571-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Bedded_chert">Bedded chert</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=2" title="Edit section: Bedded chert"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Bedded chert, also known as ribbon chert, takes the form of thinly <a href="/wiki/Bedding_(geology)" class="mw-redirect" title="Bedding (geology)">bedded</a> layers (a few centimeters to a meter in thickness<sup id="cite_ref-FOOTNOTEBlattTracy1996336_22-0" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996336-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup>) of nearly pure chert separated by very thin layers of silica-rich <a href="/wiki/Shale" title="Shale">shale</a>.<sup id="cite_ref-FOOTNOTEBoggs2006208_23-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006208-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> It is usually black to green in color, and the full sequence of beds may be several hundred meters thick. The shale is typically black shale, sometimes with <a href="/wiki/Pyrite" title="Pyrite">pyrite</a>, indicating deposition in an <a href="/wiki/Hypoxia_(environmental)" title="Hypoxia (environmental)">anoxic</a> environment.<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-1" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980571-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> Bedded chert is most often found in association with <a href="/wiki/Turbidites" class="mw-redirect" title="Turbidites">turbidites</a>, deep water <a href="/wiki/Limestone" title="Limestone">limestone</a>, submarine <a href="/wiki/Volcanic_rock" title="Volcanic rock">volcanic rock</a>,<sup id="cite_ref-FOOTNOTEBoggs2006208_23-1" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006208-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Ophiolite" title="Ophiolite">ophiolites</a>, and <a href="/wiki/M%C3%A9lange" title="Mélange">mélanges</a> on <a href="/wiki/Active_margin" class="mw-redirect" title="Active margin">active margins</a> of <a href="/wiki/Tectonic_plate" class="mw-redirect" title="Tectonic plate">tectonic plates</a>.<sup id="cite_ref-FOOTNOTEBlattTracy1996335–336_24-0" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996335–336-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Sedimentary_structures" title="Sedimentary structures">Sedimentary structures</a> are rare in bedded cherts.<sup id="cite_ref-FOOTNOTEBoggs2006208_23-2" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006208-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> The typically high purity of bedded chert, like the high purity of other chemically precipitated rock, points to deposition in areas where there is little influx of <a href="/wiki/Detrital" class="mw-redirect" title="Detrital">detrital</a> sediments (such as river water laden with silt and clay particles.)<sup id="cite_ref-FOOTNOTEBlattTracy1996335_25-0" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996335-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> Such impurities as are present include <a href="/wiki/Authigenic" class="mw-redirect" title="Authigenic">authigenic</a> pyrite and hematite, formed in the sediments after they were deposited, in addition to traces of detrital minerals.<sup id="cite_ref-FOOTNOTEBoggs2006207_8-4" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p><p>Seawater typically contains between 0.01 and 11 <a href="/wiki/Parts_per_million" class="mw-redirect" title="Parts per million">parts per million</a> (ppm) of silica, with around 1 ppm being typical. This is far below saturation, indicating that silica cannot normally be precipitated from seawater through inorganic processes. The silica is instead extracted from seawater by living organisms, such as diatoms, radiolarians, and glass sponges, which can efficiently extract silica even from very unsaturated water,<sup id="cite_ref-FOOTNOTEBoggs2006208,_211-213_26-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006208,_211-213-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> and which are estimated to presently produce 12 cubic kilometers (2.9 cu mi) of opal per year in the world's oceans.<sup id="cite_ref-FOOTNOTEBlattTracy1996338_27-0" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996338-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> Diatoms can double their numbers eight times a day under ideal conditions (though doubling once per day is more typical in normal seawater) and can extract silica from water with as little as 0.1 ppm silica.<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980578_28-0" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980578-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> The organisms protect their skeletons from dissolution by "armoring" them with metal ions. Once the organisms die, their skeletons will quickly dissolve unless they accumulate on the ocean bottom and are buried, forming siliceous ooze that is 30% to 60% silica. Thus, bedded cherts are typically composed mostly of fossil remains of organisms that secrete silica skeletons, which are usually altered by solution and recrystallization.<sup id="cite_ref-FOOTNOTEBoggs2006208,_211-213_26-1" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006208,_211-213-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> </p><p>The skeletons of these organisms are composed of opal-A, an amorphous form of silica, lacking long-range crystal structure. This is gradually transformed to opal-CT, a microcrystalline form of silica composed mostly of bladed crystals of <a href="/wiki/Cristobalite" title="Cristobalite">cristobalite</a> and <a href="/wiki/Tridymite" title="Tridymite">tridymite</a>.<sup id="cite_ref-FOOTNOTEBoggs2006214_29-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006214-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> Much opal-CT takes the form of <i>lepispheres</i>, which are clusters of bladed crystals about 10 microns in diameter.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> Opal-CT in turn transforms to microquartz. In deep ocean water, the transition to opal-CT occurs at a temperature of about 45 °C (113 °F) while the transition to microquartz occurs at a temperature of about 80 °C (176 °F). However, the transition temperature varies considerably, and the transition is hastened by the presence of <a href="/wiki/Magnesium_hydroxide" title="Magnesium hydroxide">magnesium hydroxide</a>, which provides a nucleus for the recrystallization. Megaquartz forms at elevated temperatures typical of <a href="/wiki/Metamorphism" title="Metamorphism">metamorphism</a>.<sup id="cite_ref-FOOTNOTEBoggs2006214_29-1" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006214-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> </p><p>There is evidence that the variety of chert called <a href="/wiki/Porcelainite" class="mw-redirect" title="Porcelainite">porcelainite</a>, which is characterized by a high content of opal-CT, recrystallizes at very shallow depths.<sup id="cite_ref-FOOTNOTEBoggs2006214_29-2" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006214-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> The Caballos Novaculite of Texas also shows signs of very shallow water deposition, including shallow water sedimentary structures and <a href="/wiki/Evaporite" title="Evaporite">evaporite</a> <a href="/wiki/Pseudomorphs" class="mw-redirect" title="Pseudomorphs">pseudomorphs</a>, which are casts of crystals of soluble minerals that could have formed only in near-surface conditions. This <a href="/wiki/Novaculite" title="Novaculite">novaculate</a> appears to have formed by replacement of carbonate <a href="/wiki/Fecal_pellets" class="mw-redirect" title="Fecal pellets">fecal pellets</a> by chert.<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-2" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980571-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="Subvarieties">Subvarieties</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=3" title="Edit section: Subvarieties"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Bedded cherts can be further subdivided by the kinds of organisms that produced the silica skeletons.<sup id="cite_ref-FOOTNOTEBoggs2006208_23-3" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006208-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> </p><p><i>Diatomaceous chert</i> consists of beds and lenses of <a href="/wiki/Diatomite" class="mw-redirect" title="Diatomite">diatomite</a> which were converted during <a href="/wiki/Diagenesis" title="Diagenesis">diagenesis</a> into dense, hard chert. Beds of marine diatomaceous chert comprising <a href="/wiki/Strata" class="mw-redirect" title="Strata">strata</a> several hundred meters thick have been reported from sedimentary sequences such as the <a href="/wiki/Miocene" title="Miocene">Miocene</a> <a href="/wiki/Monterey_Formation" title="Monterey Formation">Monterey Formation</a> of California and occur in rocks as old as the <a href="/wiki/Cretaceous" title="Cretaceous">Cretaceous</a>. Diatoms were the dominant siliceous organism responsible for extracting silica from seawater from the <a href="/wiki/Jurassic" title="Jurassic">Jurassic</a> and later.<sup id="cite_ref-FOOTNOTEBoggs2006208–209_31-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006208–209-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> </p><p><i><a href="/wiki/Radiolarite" title="Radiolarite">Radiolarite</a></i> consists mostly of remains of radiolarians. When the remains are well-cemented with silica, it is known as <i>radiolarian chert</i>.<sup id="cite_ref-FOOTNOTEBoggs2006209–210_32-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006209–210-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> Many show evidence of a deep-water origin, but some appear to have formed in water as shallow as 200 meters (660 ft),<sup id="cite_ref-FOOTNOTEBoggs2006210_33-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006210-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> perhaps in <a href="/wiki/Shelf_sea" class="mw-redirect" title="Shelf sea">shelf seas</a> where upwelling of nutrient-rich deep ocean water support high organic productivity.<sup id="cite_ref-FOOTNOTEBlattTracy1996336_22-1" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996336-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> Radiolarians dominated the extraction of silica from seawater prior to the Jurassic.<sup id="cite_ref-FOOTNOTEBoggs2006213_34-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006213-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup> </p><p><i>Spicularite</i> is chert composed of spicules of glass sponges and other invertebrates. When densely cemented, it is known as <i>spicular chert</i>. They are found in association with <a href="/wiki/Glauconite" title="Glauconite">glauconite</a>-rich <a href="/wiki/Sandstone" title="Sandstone">sandstone</a>, <a href="/wiki/Black_shale" class="mw-redirect" title="Black shale">black shale</a>, <a href="/wiki/Clay" title="Clay">clay</a>-rich <a href="/wiki/Limestone" title="Limestone">limestone</a>, <a href="/wiki/Phosphorite" title="Phosphorite">phosphorites</a>, and other nonvolcanic rocks typical of water a few hundred meters deep.<sup id="cite_ref-FOOTNOTEBoggs2006210_33-1" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006210-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> </p><p>Some bedded cherts appear devoid of fossils even under close microscopic examination. Their origin is uncertain, but they may form from fossil remains that are completely dissolved in fluids that then migrate to precipitate their silica load in a nearby bed.<sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-FOOTNOTEBoggs2006215–216_36-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006215–216-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Aeolian_processes" title="Aeolian processes">Eolian</a> quartz has also been suggested as a source of silica for chert beds.<sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> <a href="/wiki/Precambrian" title="Precambrian">Precambrian</a> bedded cherts are common, making up 15% of middle Precambrian sedimentary rock,<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-3" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980571-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> and may have been deposited nonbiologically in oceans more saturated in silica than the modern ocean. The high degree of silica saturation was due either to intense volcanic activity or to the lack of modern organisms that remove silica from seawater.<sup id="cite_ref-FOOTNOTEBoggs2006216_38-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006216-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Nodular_chert">Nodular chert</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=4" title="Edit section: Nodular chert"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:%C3%87%C3%B6rt_yumrusu,_Chert.2.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/7/7a/%C3%87%C3%B6rt_yumrusu%2C_Chert.2.jpg/220px-%C3%87%C3%B6rt_yumrusu%2C_Chert.2.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/7/7a/%C3%87%C3%B6rt_yumrusu%2C_Chert.2.jpg/330px-%C3%87%C3%B6rt_yumrusu%2C_Chert.2.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/7/7a/%C3%87%C3%B6rt_yumrusu%2C_Chert.2.jpg/440px-%C3%87%C3%B6rt_yumrusu%2C_Chert.2.jpg 2x" data-file-width="1024" data-file-height="768" /></a><figcaption>Chert nodule within soft limestone at <a href="/wiki/Ak%C3%A7akoca" title="Akçakoca">Akçakoca</a>, Turkey</figcaption></figure> <p>Nodular chert is most common in limestone but may also be found in <a href="/wiki/Shale" title="Shale">shales</a><sup id="cite_ref-FOOTNOTEBoggs2006216_38-1" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006216-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> and sandstones.<sup id="cite_ref-FOOTNOTEBlattTracy1996335_25-1" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996335-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> It is less common in <a href="/wiki/Dolomite_(rock)" title="Dolomite (rock)">dolomite</a>.<sup id="cite_ref-Knauth1979_1-1" class="reference"><a href="#cite_note-Knauth1979-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Nodular chert in <a href="/wiki/Carbonate_rock" title="Carbonate rock">carbonate rocks</a> is found as oval to irregular <a href="/wiki/Nodule_(geology)" title="Nodule (geology)">nodules</a>. These vary in size from powdery quartz particles to nodules several meters in size. The nodules are most typically along bedding planes or <a href="/wiki/Stylolite" title="Stylolite">stylolite</a> (dissolution) surfaces, where fossil organisms tended to accumulate and provided a source of dissolved silica, but they are sometimes found cutting across bedding surfaces, where the chert fills <a href="/wiki/Fossil_burrow" class="mw-redirect" title="Fossil burrow">fossil burrows</a>, <a href="/wiki/Fluid_escape_structures" class="mw-redirect" title="Fluid escape structures">fluid escape structures</a>, or fractures. Nodules under a few centimeters in size tend to be egg-shaped, while larger nodules form irregular bodies with knobby surfaces. The outer few centimeters of large nodules may show <a href="/wiki/Desiccation" title="Desiccation">desiccation</a> cracks with secondary chert, which likely formed at the same time as the nodule. Calcareous fossils are occasionally present that have been completely silicified.<sup id="cite_ref-FOOTNOTEBlattTracy1996335_25-2" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996335-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> Where chert occurs in chalk or <a href="/wiki/Marl" title="Marl">marl</a>, it is usually called <a href="/wiki/Flint" title="Flint">flint</a>.<sup id="cite_ref-FOOTNOTEBoggs2006207_8-5" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Flint_with_weathered_crust.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Flint_with_weathered_crust.JPG/220px-Flint_with_weathered_crust.JPG" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Flint_with_weathered_crust.JPG/330px-Flint_with_weathered_crust.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Flint_with_weathered_crust.JPG/440px-Flint_with_weathered_crust.JPG 2x" data-file-width="3648" data-file-height="2736" /></a><figcaption>Flint with white weathered crust</figcaption></figure> <p>Nodular chert is often dark in color.<sup id="cite_ref-FOOTNOTEBlattTracy1996335_25-3" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996335-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> It can have a white <a href="/wiki/Weathering" title="Weathering">weathering</a> rind that is known in <a href="/wiki/Archaeology" title="Archaeology">archaeology</a> as <i><a href="/wiki/Cortex_(archaeology)" title="Cortex (archaeology)">cortex</a></i>. </p><p>Most chert nodules have <a href="/wiki/Texture_(geology)" title="Texture (geology)">textures</a> suggesting they were formed by diagenetic replacement, where silica was deposited in place of <a href="/wiki/Calcium_carbonate" title="Calcium carbonate">calcium carbonate</a> or <a href="/wiki/Clay_mineral" title="Clay mineral">clay minerals</a>.<sup id="cite_ref-FOOTNOTEBoggs2006207_8-6" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> This may have taken place where <a href="/wiki/Meteoric_water" title="Meteoric water">meteoric water</a> (water derived from snow or rain) mixed with saltwater in the sediment beds, where carbon dioxide was trapped, producing an environment supersaturated with silica and undersaturated with calcium carbonate.<sup id="cite_ref-Knauth1979_1-2" class="reference"><a href="#cite_note-Knauth1979-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Nodular chert is particularly common in continental shelf environments.<sup id="cite_ref-FOOTNOTEBoggs2006216_38-2" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006216-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> In the <a href="/wiki/Permian_Basin_(North_America)" title="Permian Basin (North America)">Permian Basin (North America)</a>, chert nodules and chertified fossils are abundant in basin limestones, but there is little in the carbonate buildup zone itself. This may reflect dissolution of opal where carbonate is being actively deposited, a lack of siliceous organisms in these environments, or removal of siliceous skeletons by strong currents that redeposit the siliceous material in the deep basin.<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980576_39-0" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980576-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup> </p><p>The silica in nodular chert likely precipitates as opal-A, based on internal banding in nodules,<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980576_39-1" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980576-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup> and may recrystallize directly to microquartz without first recrystallizing to opal-CT.<sup id="cite_ref-FOOTNOTEBoggs2006216_38-3" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006216-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> Some nodular chert may precipitate directly as microquartz, due to low levels of supersaturation of silica.<sup id="cite_ref-FOOTNOTEBlattTracy1996335_25-4" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996335-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Other_occurrences">Other occurrences</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=5" title="Edit section: Other occurrences"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <a href="/wiki/Banded_iron_formation" title="Banded iron formation">banded iron formations</a> of <a href="/wiki/Precambrian" title="Precambrian">Precambrian</a> age are composed of alternating layers of chert and <a href="/wiki/Iron_oxide" title="Iron oxide">iron oxides</a>.<sup id="cite_ref-FOOTNOTEBoggs2006217–218_40-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006217–218-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-FOOTNOTEBlattTracy1996339–343_41-0" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996339–343-41"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup> </p><p>Nonmarine cherts may form in saline alkaline lakes as thin lenses or nodules showing sedimentary structures suggestive of <a href="/wiki/Evaporite" title="Evaporite">evaporite</a> origin. Such cherts are forming today in the alkaline lakes of the <a href="/wiki/East_African_Rift_Valley" class="mw-redirect" title="East African Rift Valley">East African Rift Valley</a>.<sup id="cite_ref-FOOTNOTEBlattTracy1996336–337_42-0" class="reference"><a href="#cite_note-FOOTNOTEBlattTracy1996336–337-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup> These lakes are characterized by <a href="/wiki/Sodium_carbonate" title="Sodium carbonate">sodium carbonate</a> brines with very high <a href="/wiki/PH" title="PH">pH</a> that can contain as much as 2700 ppm silica. Episodes of runoff of fresh water into the lakes lowers the pH and precipitates the unusual <a href="/wiki/Sodium_silicate" title="Sodium silicate">sodium silicate</a> minerals <a href="/wiki/Magadiite" title="Magadiite">magadiite</a> or <a href="/wiki/Kenyaite" title="Kenyaite">kenyaite</a>, After burial and <a href="/wiki/Diagenesis" title="Diagenesis">diagenesis</a>, these are altered to Magadi-type chert.<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980576_39-2" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980576-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup> The <a href="/wiki/Morrison_Formation" title="Morrison Formation">Morrison Formation</a> contains Magadi-type chert that may have formed in the alkaline Lake T'oo'dichi'.<sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup> </p><p>Chert may also form from replacement of <a href="/wiki/Calcrete" class="mw-redirect" title="Calcrete">calcrete</a> in fossil soils (<a href="/wiki/Paleosols" class="mw-redirect" title="Paleosols">paleosols</a>) by silica dissolved from overlying <a href="/wiki/Volcanic_ash" title="Volcanic ash">volcanic ash</a> beds.<sup id="cite_ref-44" class="reference"><a href="#cite_note-44"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Fossils">Fossils</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=6" title="Edit section: Fossils"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Tung_Ping_Chau_6.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Tung_Ping_Chau_6.jpg/220px-Tung_Ping_Chau_6.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Tung_Ping_Chau_6.jpg/330px-Tung_Ping_Chau_6.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a3/Tung_Ping_Chau_6.jpg/440px-Tung_Ping_Chau_6.jpg 2x" data-file-width="1600" data-file-height="1200" /></a><figcaption>An erosion resistant layer of chert in the <a href="/wiki/Eocene" title="Eocene">Eocene</a> <a href="/w/index.php?title=Ping_Chau_Formation&action=edit&redlink=1" class="new" title="Ping Chau Formation (page does not exist)">Ping Chau Formation</a>, Hong Kong</figcaption></figure> <p>The <a href="/wiki/Cryptocrystalline" title="Cryptocrystalline">cryptocrystalline</a> nature of chert, combined with its above average ability to resist weathering, <a href="/wiki/Recrystallization_(geology)" title="Recrystallization (geology)">recrystallization</a> and <a href="/wiki/Metamorphism" title="Metamorphism">metamorphism</a> has made it an ideal rock for preservation of early life forms.<sup id="cite_ref-45" class="reference"><a href="#cite_note-45"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup> </p><p>For example: </p> <ul><li>The 3.2 <a href="/wiki/Gya_(unit)" class="mw-redirect" title="Gya (unit)">Ga</a> chert of the <a href="/wiki/Fig_Tree_Formation" title="Fig Tree Formation">Fig Tree Formation</a> in the Barberton Mountains between <a href="/wiki/Eswatini" title="Eswatini">Eswatini</a> and South Africa preserved non-colonial <a href="/wiki/Unicellular" class="mw-redirect" title="Unicellular">unicellular</a> bacteria-like fossils.<sup id="cite_ref-46" class="reference"><a href="#cite_note-46"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-47" class="reference"><a href="#cite_note-47"><span class="cite-bracket">[</span>47<span class="cite-bracket">]</span></a></sup></li> <li>The <a href="/wiki/Gunflint_Chert" class="mw-redirect" title="Gunflint Chert">Gunflint Chert</a> of western Ontario (1.9 to 2.3 Ga) preserves not only bacteria and <a href="/wiki/Cyanobacteria" title="Cyanobacteria">cyanobacteria</a> but also organisms believed to be ammonia-consuming and some that resemble <a href="/wiki/Green_algae" title="Green algae">green algae</a> and fungus-like organisms.<sup id="cite_ref-48" class="reference"><a href="#cite_note-48"><span class="cite-bracket">[</span>48<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-49" class="reference"><a href="#cite_note-49"><span class="cite-bracket">[</span>49<span class="cite-bracket">]</span></a></sup></li> <li>The <a href="/wiki/Apex_Chert" class="mw-redirect" title="Apex Chert">Apex Chert</a> (3.4 Ga) of the <a href="/wiki/Pilbara_craton" class="mw-redirect" title="Pilbara craton">Pilbara craton</a>, Australia preserved eleven taxa of <a href="/wiki/Prokaryotes" class="mw-redirect" title="Prokaryotes">prokaryotes</a>.<sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span class="cite-bracket">[</span>50<span class="cite-bracket">]</span></a></sup> However, these findings have been disputed.<sup id="cite_ref-51" class="reference"><a href="#cite_note-51"><span class="cite-bracket">[</span>51<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-52" class="reference"><a href="#cite_note-52"><span class="cite-bracket">[</span>52<span class="cite-bracket">]</span></a></sup></li> <li>The <a href="/wiki/Bitter_Springs_Group" title="Bitter Springs Group">Bitter Springs Formation</a> of the <a href="/wiki/Amadeus_Basin" title="Amadeus Basin">Amadeus Basin</a>, Central Australia, preserves 850 Ma cyanobacteria and algae.<sup id="cite_ref-53" class="reference"><a href="#cite_note-53"><span class="cite-bracket">[</span>53<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-54" class="reference"><a href="#cite_note-54"><span class="cite-bracket">[</span>54<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-55" class="reference"><a href="#cite_note-55"><span class="cite-bracket">[</span>55<span class="cite-bracket">]</span></a></sup></li> <li>The <a href="/wiki/Rhynie_chert" title="Rhynie chert">Rhynie chert</a> (410 Ma) of Scotland has remains of a <a href="/wiki/Devonian" title="Devonian">Devonian</a> land flora and fauna with preservation so perfect that it allows cellular studies of the fossils.<sup id="cite_ref-GarwoodOliver2019_56-0" class="reference"><a href="#cite_note-GarwoodOliver2019-56"><span class="cite-bracket">[</span>56<span class="cite-bracket">]</span></a></sup></li></ul> <div class="mw-heading mw-heading2"><h2 id="Prehistoric_and_historic_uses">Prehistoric and historic uses</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=7" title="Edit section: Prehistoric and historic uses"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Chert is of only modest economic importance today as a source of silica (quartz sand being much more important.) However, chert deposits may be associated with valuable deposits of <a href="/wiki/Iron" title="Iron">iron</a>, <a href="/wiki/Uranium" title="Uranium">uranium</a>, <a href="/wiki/Manganese" title="Manganese">manganese</a>, <a href="/wiki/Phosphorite" title="Phosphorite">phosphorite</a>, and <a href="/wiki/Petroleum" title="Petroleum">petroleum</a>.<sup id="cite_ref-FOOTNOTEBoggs2006206_57-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006206-57"><span class="cite-bracket">[</span>57<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Tools">Tools</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=8" title="Edit section: Tools"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Mill_Creek_chert_hoe_and_other_artifacts_Parkin_HRoe_01.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/30/Mill_Creek_chert_hoe_and_other_artifacts_Parkin_HRoe_01.jpg/200px-Mill_Creek_chert_hoe_and_other_artifacts_Parkin_HRoe_01.jpg" decoding="async" width="200" height="211" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/30/Mill_Creek_chert_hoe_and_other_artifacts_Parkin_HRoe_01.jpg/300px-Mill_Creek_chert_hoe_and_other_artifacts_Parkin_HRoe_01.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/30/Mill_Creek_chert_hoe_and_other_artifacts_Parkin_HRoe_01.jpg/400px-Mill_Creek_chert_hoe_and_other_artifacts_Parkin_HRoe_01.jpg 2x" data-file-width="800" data-file-height="843" /></a><figcaption><a href="/wiki/Mill_Creek_chert" title="Mill Creek chert">Mill Creek chert</a> from the <a href="/wiki/Parkin_Archeological_State_Park" title="Parkin Archeological State Park">Parkin Site</a> in <a href="/wiki/Arkansas" title="Arkansas">Arkansas</a></figcaption></figure> <p>In prehistoric times, chert was often used as a raw material for the construction of <a href="/wiki/Stone_tool" title="Stone tool">stone tools</a>. Like <a href="/wiki/Obsidian" title="Obsidian">obsidian</a>, as well as some <a href="/wiki/Rhyolite" title="Rhyolite">rhyolites</a>, <a href="/wiki/Felsite" title="Felsite">felsites</a>, <a href="/wiki/Quartzite" title="Quartzite">quartzites</a>, and other <a href="/wiki/Tool_stone" title="Tool stone">tool stones</a> used in <a href="/wiki/Lithic_reduction" title="Lithic reduction">lithic reduction</a>, chert fractures in a <a href="/wiki/Hertzian_cone" title="Hertzian cone">Hertzian cone</a> when struck with sufficient force. This results in <a href="/wiki/Conchoidal" class="mw-redirect" title="Conchoidal">conchoidal</a> fractures, a characteristic of all minerals with no <a href="/wiki/Cleavage_(crystal)" title="Cleavage (crystal)">cleavage</a> planes. In this kind of fracture, a cone of force propagates through the material from the point of impact, eventually removing a full or partial cone, like when a plate-glass window is struck by a small object such as an <a href="/wiki/Air_gun" title="Air gun">air gun</a> projectile. The partial Hertzian cones produced during lithic reduction are called <a href="/wiki/Lithic_flake" title="Lithic flake">flakes</a>, and exhibit features characteristic of this sort of breakage, including <a href="/wiki/Striking_platform" title="Striking platform">striking platforms</a>, <a href="/wiki/Bulb_of_force" class="mw-redirect" title="Bulb of force">bulbs of force</a>, and occasionally <a href="/wiki/Eraillure" title="Eraillure">eraillures</a>, which are small secondary flakes detached from the flake's bulb of force.<sup id="cite_ref-58" class="reference"><a href="#cite_note-58"><span class="cite-bracket">[</span>58<span class="cite-bracket">]</span></a></sup> </p><p>When a chert stone is struck against an iron-bearing surface, sparks result. This makes chert an excellent tool for starting fires, and both flint and common chert were used in various types of fire-starting tools, such as <a href="/wiki/Tinderbox" title="Tinderbox">tinderboxes</a>, throughout history. A primary historic use of common chert and flint was for <a href="/wiki/Flintlock" title="Flintlock">flintlock</a> <a href="/wiki/Firearms" class="mw-redirect" title="Firearms">firearms</a>, in which the chert striking a metal plate produces a spark that ignites a small reservoir containing <a href="/wiki/Black_powder" class="mw-redirect" title="Black powder">black powder</a>, discharging the firearm.<sup id="cite_ref-:0_2-1" class="reference"><a href="#cite_note-:0-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-59" class="reference"><a href="#cite_note-59"><span class="cite-bracket">[</span>59<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Construction">Construction</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=9" title="Edit section: Construction"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Cherts can cause several problems when used as concrete aggregates. Deeply weathered chert develops surface pop-outs when used in concrete that undergoes freezing and thawing because of the high porosity of weathered chert. The other concern is that certain cherts undergo an alkali-silica reaction with high-alkali cements. This reaction leads to cracking and expansion of concrete and ultimately to failure of the material.<sup id="cite_ref-60" class="reference"><a href="#cite_note-60"><span class="cite-bracket">[</span>60<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Varieties">Varieties</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=10" title="Edit section: Varieties"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>There are numerous varieties of chert, classified based on their visible, microscopic and physical characteristics.<sup id="cite_ref-roberts-etal-1990_9-1" class="reference"><a href="#cite_note-roberts-etal-1990-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-mitchell-1985_10-1" class="reference"><a href="#cite_note-mitchell-1985-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> Examples are: </p> <ul><li><a href="/wiki/Flint" title="Flint">Flint</a> is a compact microcrystalline quartz. It was originally the name for chert found in <a href="/wiki/Chalk" title="Chalk">chalk</a> or marly limestone formations formed by a replacement of calcium carbonate with <a href="/wiki/Silica" class="mw-redirect" title="Silica">silica</a>. Commonly found as nodules, this variety was often used in past times to make bladed tools. Today, some geologists refer to any dark gray to black chert as flint.<sup id="cite_ref-FOOTNOTEBatesJackson1984"Flint"_61-0" class="reference"><a href="#cite_note-FOOTNOTEBatesJackson1984"Flint"-61"><span class="cite-bracket">[</span>61<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-62" class="reference"><a href="#cite_note-62"><span class="cite-bracket">[</span>62<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-63" class="reference"><a href="#cite_note-63"><span class="cite-bracket">[</span>63<span class="cite-bracket">]</span></a></sup> The dark color is from inclusions of organic matter.<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-4" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980571-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> Among non-geologists, the distinction between "flint" and "chert" is often one of quality – chert being lower quality than flint. This usage of the terminology is particularly prevalent in Great Britain where most true flint (found in chalk formations) was of better quality than "common chert" (from limestone formations).<sup id="cite_ref-64" class="reference"><a href="#cite_note-64"><span class="cite-bracket">[</span>64<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li>"Common chert" is a variety of chert which forms in limestone formations by replacement of calcium carbonate with silica. This is the most abundantly found variety of chert. It is generally considered to be less attractive for producing gem stones and bladed tools than flint.</li></ul> <ul><li><a href="/wiki/Jasper" title="Jasper">Jasper</a> is a variety of chert formed as primary deposits, found in or in connection with magmatic formations, and owes its typical red color to hematite inclusions. Jasper frequently also occurs in black, yellow and green, depending on the type of iron it contains. Jasper is usually opaque to near opaque.<sup id="cite_ref-FOOTNOTEBatesJackson1984"Jasper"_65-0" class="reference"><a href="#cite_note-FOOTNOTEBatesJackson1984"Jasper"-65"><span class="cite-bracket">[</span>65<span class="cite-bracket">]</span></a></sup> Jasper is also present in banded iron formation, where it is described as jaspilite.<sup id="cite_ref-FOOTNOTEBoggs2006207_8-7" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li>Radiolarite is a variety of chert formed as primary deposits and containing <a href="/wiki/Radiolarian" class="mw-redirect" title="Radiolarian">radiolarian</a> microfossils.<sup id="cite_ref-FOOTNOTEBoggs2006209–210_32-1" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006209–210-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> Many show evidence of a deep-water origin, but some appear to have formed in water as shallow as 200 meters (660 ft).<sup id="cite_ref-FOOTNOTEBoggs2006209–210_32-2" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006209–210-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li><a href="/wiki/Chalcedony" title="Chalcedony">Chalcedony</a> is a microfibrous quartz.<sup id="cite_ref-FOOTNOTEBoggs2006206–207_16-2" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006206–207-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li><a href="/wiki/Agate" title="Agate">Agate</a> is distinctly banded chalcedony with successive layers differing in color or value.<sup id="cite_ref-66" class="reference"><a href="#cite_note-66"><span class="cite-bracket">[</span>66<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li><a href="/wiki/Onyx" title="Onyx">Onyx</a> is a banded agate with layers in parallel lines, often black and white (<i>sardonyx</i>).<sup id="cite_ref-FOOTNOTEKleinHurlbut1993529_67-0" class="reference"><a href="#cite_note-FOOTNOTEKleinHurlbut1993529-67"><span class="cite-bracket">[</span>67<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li><a href="/w/index.php?title=Magadi-type_chert&action=edit&redlink=1" class="new" title="Magadi-type chert (page does not exist)">Magadi-type chert</a> is a variety that forms from a sodium silicate precursor in highly alkaline lakes such as <a href="/wiki/Lake_Magadi" title="Lake Magadi">Lake Magadi</a> in Kenya.<sup id="cite_ref-68" class="reference"><a href="#cite_note-68"><span class="cite-bracket">[</span>68<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li><a href="/wiki/Novaculite" title="Novaculite">Novaculite</a> is a very dense, fine-grained, and uniform form of very pure white chert with a high content of extracrystalline water.<sup id="cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-5" class="reference"><a href="#cite_note-FOOTNOTEBlattMiddletonMurray1980571-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> It is most common in the mid-<a href="/wiki/Paleozoic" title="Paleozoic">Paleozoic</a> rocks of <a href="/wiki/Texas" title="Texas">Texas</a>, <a href="/wiki/Oklahoma" title="Oklahoma">Oklahoma</a>, and <a href="/wiki/Arkansas" title="Arkansas">Arkansas</a> in the south-central United States, where it has undergone some <a href="/wiki/Metamorphism" title="Metamorphism">metamorphism</a>.<sup id="cite_ref-FOOTNOTEBoggs2006207_8-8" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li>Porcelanite is a term used for fine-grained siliceous rocks with a texture and a fracture resembling those of unglazed porcelain. It likely forms in shallow water and is composed mostly of opal-CT.<sup id="cite_ref-FOOTNOTEBoggs2006207,_214_69-0" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207,_214-69"><span class="cite-bracket">[</span>69<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li><a href="/wiki/Rotten_stone" title="Rotten stone">Tripolitic chert</a> (or tripoli) is a light-colored porous friable siliceous (largely chalcedonic) sedimentary rock, which results from the weathering (decalcification) of chert or siliceous limestone.<sup id="cite_ref-FOOTNOTEBatesJackson1984"Tripoli"_70-0" class="reference"><a href="#cite_note-FOOTNOTEBatesJackson1984"Tripoli"-70"><span class="cite-bracket">[</span>70<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li><a href="/wiki/Siliceous_sinter" class="mw-redirect" title="Siliceous sinter">Siliceous sinter</a> is porous, low-density, light-colored siliceous rock deposited by waters of hot springs and geysers.<sup id="cite_ref-FOOTNOTEBoggs2006207_8-9" class="reference"><a href="#cite_note-FOOTNOTEBoggs2006207-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup></li></ul> <ul><li><a href="/wiki/Mozarkite" title="Mozarkite">Mozarkite</a> a varicolored, easily polished Ordovician chert that takes a high polish. It is the state rock of Missouri.<sup id="cite_ref-FOOTNOTEBatesJackson1984"Mozarkite"_71-0" class="reference"><a href="#cite_note-FOOTNOTEBatesJackson1984"Mozarkite"-71"><span class="cite-bracket">[</span>71<span class="cite-bracket">]</span></a></sup></li></ul> <p>Other lesser used archaic terms for chert are firestone and silex.<sup id="cite_ref-FOOTNOTEBatesJackson1984_72-0" class="reference"><a href="#cite_note-FOOTNOTEBatesJackson1984-72"><span class="cite-bracket">[</span>72<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=11" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Petrology" title="Petrology">Petrology</a> – Branch of geology that studies the formation, composition, distribution and structure of rocks <ul><li><a href="/wiki/Eolith" title="Eolith">Eolith</a> – Knapped flint nodule</li> <li><a href="/wiki/Nodule_(geology)" title="Nodule (geology)">Nodule (geology)</a> – Small mass of a mineral with a contrasting composition to the enclosing sediment or rock not to be confused with <a href="/wiki/Concretion" title="Concretion">Concretion</a></li> <li><a href="/wiki/Obsidian" title="Obsidian">Obsidian</a> – Naturally occurring volcanic glass</li> <li><a href="/wiki/Opal" title="Opal">Opal</a> – Hydrated amorphous form of silica</li> <li><a href="/wiki/Whinstone" title="Whinstone">Whinstone</a> – Quarrying term for any hard dark-coloured rock</li></ul></li> <li><a href="/wiki/Archaeology" title="Archaeology">Archaeology</a> – Study of human activity based on materials that people have left behind <ul><li><a href="/wiki/Clovis_point" title="Clovis point">Clovis points</a>, archaeological artefacts of the <a href="/wiki/Clovis_culture" title="Clovis culture">Clovis culture</a> in <a href="/wiki/New_Mexico" title="New Mexico">New Mexico</a></li> <li><a href="/wiki/Piatra_Tomii" title="Piatra Tomii">Piatra Tomii</a> – Late Jurassic limestone outcrop, a prehistoric chert mine in <a href="/wiki/Alba_County" title="Alba County">Alba County</a>, Romania</li> <li><a href="/wiki/Tranchet_axe" title="Tranchet axe">Tranchet axe</a></li></ul></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Chert&action=edit&section=12" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-Knauth1979-1"><span class="mw-cite-backlink">^ <a href="#cite_ref-Knauth1979_1-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Knauth1979_1-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-Knauth1979_1-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFKnauth1979" class="citation journal cs1">Knauth, L. Paul (1 June 1979). "A model for the origin of chert in limestone". <i>Geology</i>. <b>7</b> (6): <span class="nowrap">274–</span>77. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1979Geo.....7..274K">1979Geo.....7..274K</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1130%2F0091-7613%281979%297%3C274%3AAMFTOO%3E2.0.CO%3B2">10.1130/0091-7613(1979)7<274:AMFTOO>2.0.CO;2</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Geology&rft.atitle=A+model+for+the+origin+of+chert+in+limestone&rft.volume=7&rft.issue=6&rft.pages=%3Cspan+class%3D%22nowrap%22%3E274-%3C%2Fspan%3E77&rft.date=1979-06-01&rft_id=info%3Adoi%2F10.1130%2F0091-7613%281979%297%3C274%3AAMFTOO%3E2.0.CO%3B2&rft_id=info%3Abibcode%2F1979Geo.....7..274K&rft.aulast=Knauth&rft.aufirst=L.+Paul&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-:0-2"><span class="mw-cite-backlink">^ <a href="#cite_ref-:0_2-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-:0_2-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://geology.com/rocks/chert.shtml">"Chert: Sedimentary Rock - Pictures, Definition, Formation"</a>. <i>geology.com</i><span class="reference-accessdate">. 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Mitchell, "Dictionary of Rocks", 1985. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-442-26328-7" title="Special:BookSources/0-442-26328-7">0-442-26328-7</a></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFMcBrideFolk1977" class="citation journal cs1">McBride, E.F.; Folk, R.L. (1977). "The Caballos Novaculite Revisited: Part II: Chert and Shale Members and Synthesis". <i>SEPM Journal of Sedimentary Research</i>. <b>47</b>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1306%2F212F731A-2B24-11D7-8648000102C1865D">10.1306/212F731A-2B24-11D7-8648000102C1865D</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=SEPM+Journal+of+Sedimentary+Research&rft.atitle=The+Caballos+Novaculite+Revisited%3A+Part+II%3A+Chert+and+Shale+Members+and+Synthesis&rft.volume=47&rft.date=1977&rft_id=info%3Adoi%2F10.1306%2F212F731A-2B24-11D7-8648000102C1865D&rft.aulast=McBride&rft.aufirst=E.F.&rft.au=Folk%2C+R.L.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFThurston1972" class="citation journal cs1">Thurston, Diana R. (1972). "Studies on bedded cherts". <i>Contributions to Mineralogy and Petrology</i>. <b>36</b> (4): <span class="nowrap">329–</span>334. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1972CoMP...36..329T">1972CoMP...36..329T</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2FBF00444339">10.1007/BF00444339</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:128745664">128745664</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Contributions+to+Mineralogy+and+Petrology&rft.atitle=Studies+on+bedded+cherts&rft.volume=36&rft.issue=4&rft.pages=%3Cspan+class%3D%22nowrap%22%3E329-%3C%2Fspan%3E334&rft.date=1972&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A128745664%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1007%2FBF00444339&rft_id=info%3Abibcode%2F1972CoMP...36..329T&rft.aulast=Thurston&rft.aufirst=Diana+R.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-Folk1980-13"><span class="mw-cite-backlink">^ <a href="#cite_ref-Folk1980_13-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Folk1980_13-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFFolk1980" class="citation book cs1">Folk, R.L. (1980). <a rel="nofollow" class="external text" href="https://repositories.lib.utexas.edu/handle/2152/22930"><i>Petrology of Sedimentary Rocks</i></a>. Austin, Texas: Hemphill. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780914696148" title="Special:BookSources/9780914696148"><bdi>9780914696148</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Petrology+of+Sedimentary+Rocks&rft.place=Austin%2C+Texas&rft.pub=Hemphill&rft.date=1980&rft.isbn=9780914696148&rft.aulast=Folk&rft.aufirst=R.L.&rft_id=https%3A%2F%2Frepositories.lib.utexas.edu%2Fhandle%2F2152%2F22930&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFBlattTracy1996" class="citation book cs1">Blatt, Harvey; Tracy, Robert J. 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href="#cite_ref-FOOTNOTEBoggs2006206–207_16-2"><sup><i><b>c</b></i></sup></a></span> <span class="reference-text"><a href="#CITEREFBoggs2006">Boggs 2006</a>, pp. 206–207.</span> </li> <li id="cite_note-FOOTNOTEBlattMiddletonMurray1980572-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBlattMiddletonMurray1980572_17-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBlattMiddletonMurray1980">Blatt, Middleton & Murray 1980</a>, p. 572.</span> </li> <li id="cite_note-FOOTNOTEBlattTracy1996336–338-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBlattTracy1996336–338_18-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBlattTracy1996">Blatt & Tracy 1996</a>, pp. 336–338.</span> </li> <li id="cite_note-FOOTNOTEBlattMiddletonMurray1980575-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBlattMiddletonMurray1980575_19-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBlattMiddletonMurray1980">Blatt, Middleton & Murray 1980</a>, p. 575.</span> </li> <li id="cite_note-FOOTNOTEBlattTracy1996339-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBlattTracy1996339_20-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBlattTracy1996">Blatt & Tracy 1996</a>, pp. 339.</span> </li> <li id="cite_note-FOOTNOTEBlattMiddletonMurray1980571-21"><span class="mw-cite-backlink">^ <a href="#cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-1"><sup><i><b>b</b></i></sup></a> <a href="#cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-2"><sup><i><b>c</b></i></sup></a> <a href="#cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-3"><sup><i><b>d</b></i></sup></a> <a href="#cite_ref-FOOTNOTEBlattMiddletonMurray1980571_21-4"><sup><i><b>e</b></i></sup></a> <a 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"3.46 Ga Apex chert 'microfossils' reinterpreted as mineral artefacts produced during phyllosilicate exfoliation". <i>Gondwana Research</i>. <b>36</b>: <span class="nowrap">296–</span>313. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2016GondR..36..296W">2016GondR..36..296W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.gr.2015.07.010">10.1016/j.gr.2015.07.010</a>. <a href="/wiki/Hdl_(identifier)" class="mw-redirect" title="Hdl (identifier)">hdl</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://hdl.handle.net/2164%2F9044">2164/9044</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Gondwana+Research&rft.atitle=3.46+Ga+Apex+chert+%27microfossils%27+reinterpreted+as+mineral+artefacts+produced+during+phyllosilicate+exfoliation&rft.volume=36&rft.pages=%3Cspan+class%3D%22nowrap%22%3E296-%3C%2Fspan%3E313&rft.date=2016-08&rft_id=info%3Ahdl%2F2164%2F9044&rft_id=info%3Adoi%2F10.1016%2Fj.gr.2015.07.010&rft_id=info%3Abibcode%2F2016GondR..36..296W&rft.aulast=Wacey&rft.aufirst=David&rft.au=Saunders%2C+Martin&rft.au=Kong%2C+Charlie&rft.au=Brasier%2C+Alexander&rft.au=Brasier%2C+Martin&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-53"><span class="mw-cite-backlink"><b><a href="#cite_ref-53">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFSchopf1968" class="citation journal cs1">Schopf, J. William (1968). "Microflora of the Bitter Springs Formation, Late Precambrian, Central Australia". <i>Journal of Paleontology</i>. <b>42</b> (3): <span class="nowrap">651–</span>88. <a href="/wiki/JSTOR_(identifier)" class="mw-redirect" title="JSTOR (identifier)">JSTOR</a> <a rel="nofollow" class="external text" href="https://www.jstor.org/stable/1302368.">1302368.</a></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Paleontology&rft.atitle=Microflora+of+the+Bitter+Springs+Formation%2C+Late+Precambrian%2C+Central+Australia&rft.volume=42&rft.issue=3&rft.pages=%3Cspan+class%3D%22nowrap%22%3E651-%3C%2Fspan%3E88&rft.date=1968&rft_id=https%3A%2F%2Fwww.jstor.org%2Fstable%2F1302368.%23id-name%3DJSTOR&rft.aulast=Schopf&rft.aufirst=J.+William&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-54"><span class="mw-cite-backlink"><b><a href="#cite_ref-54">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.ucmp.berkeley.edu/precambrian/bittersprings.html">Cyanobacertial fossils of the Bitter Springs Chert, UMCP Berkeley</a></span> </li> <li id="cite_note-55"><span class="mw-cite-backlink"><b><a href="#cite_ref-55">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFWaceyEiloartSaunders2019" class="citation journal cs1">Wacey, David; Eiloart, Kate; Saunders, Martin (November 2019). <a rel="nofollow" class="external text" href="https://doi.org/10.1144%2Fjgs2019-053">"Comparative multi-scale analysis of filamentous microfossils from the c. 850 Ma Bitter Springs Group and filaments from the c. 3460 Ma Apex chert"</a>. <i>Journal of the Geological Society</i>. <b>176</b> (6): <span class="nowrap">1247–</span>1260. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2019JGSoc.176.1247W">2019JGSoc.176.1247W</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1144%2Fjgs2019-053">10.1144/jgs2019-053</a></span>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:189976198">189976198</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+the+Geological+Society&rft.atitle=Comparative+multi-scale+analysis+of+filamentous+microfossils+from+the+c.+850+Ma+Bitter+Springs+Group+and+filaments+from+the+c.+3460+Ma+Apex+chert&rft.volume=176&rft.issue=6&rft.pages=%3Cspan+class%3D%22nowrap%22%3E1247-%3C%2Fspan%3E1260&rft.date=2019-11&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A189976198%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1144%2Fjgs2019-053&rft_id=info%3Abibcode%2F2019JGSoc.176.1247W&rft.aulast=Wacey&rft.aufirst=David&rft.au=Eiloart%2C+Kate&rft.au=Saunders%2C+Martin&rft_id=https%3A%2F%2Fdoi.org%2F10.1144%252Fjgs2019-053&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-GarwoodOliver2019-56"><span class="mw-cite-backlink"><b><a href="#cite_ref-GarwoodOliver2019_56-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFGarwoodOliverSpencer2019" class="citation journal cs1">Garwood, Russell J; Oliver, Heather; Spencer, Alan R T (2019). <a rel="nofollow" class="external text" href="https://www.research.manchester.ac.uk/portal/en/publications/an-introduction-to-the-rhynie-chert(19df3309-02af-4d25-b75b-1299cf541fac).html">"An introduction to the Rhynie chert"</a>. <i>Geological Magazine</i>. <b>157</b> (1): <span class="nowrap">47–</span>64. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1017%2FS0016756819000670">10.1017/S0016756819000670</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0016-7568">0016-7568</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:182210855">182210855</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Geological+Magazine&rft.atitle=An+introduction+to+the+Rhynie+chert&rft.volume=157&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E47-%3C%2Fspan%3E64&rft.date=2019&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A182210855%23id-name%3DS2CID&rft.issn=0016-7568&rft_id=info%3Adoi%2F10.1017%2FS0016756819000670&rft.aulast=Garwood&rft.aufirst=Russell+J&rft.au=Oliver%2C+Heather&rft.au=Spencer%2C+Alan+R+T&rft_id=https%3A%2F%2Fwww.research.manchester.ac.uk%2Fportal%2Fen%2Fpublications%2Fan-introduction-to-the-rhynie-chert%2819df3309-02af-4d25-b75b-1299cf541fac%29.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTEBoggs2006206-57"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBoggs2006206_57-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBoggs2006">Boggs 2006</a>, p. 206.</span> </li> <li id="cite_note-58"><span class="mw-cite-backlink"><b><a href="#cite_ref-58">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFJennings2011" class="citation journal cs1">Jennings, Thomas A. (December 2011). "Experimental production of bending and radial flake fractures and implications for lithic technologies". <i>Journal of Archaeological Science</i>. <b>38</b> (12): <span class="nowrap">3644–</span>3651. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2011JArSc..38.3644J">2011JArSc..38.3644J</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.jas.2011.08.035">10.1016/j.jas.2011.08.035</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Journal+of+Archaeological+Science&rft.atitle=Experimental+production+of+bending+and+radial+flake+fractures+and+implications+for+lithic+technologies&rft.volume=38&rft.issue=12&rft.pages=%3Cspan+class%3D%22nowrap%22%3E3644-%3C%2Fspan%3E3651&rft.date=2011-12&rft_id=info%3Adoi%2F10.1016%2Fj.jas.2011.08.035&rft_id=info%3Abibcode%2F2011JArSc..38.3644J&rft.aulast=Jennings&rft.aufirst=Thomas+A.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-59"><span class="mw-cite-backlink"><b><a href="#cite_ref-59">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFRoetsEngelbrechtHolland2014" class="citation journal cs1">Roets, Michael; Engelbrecht, William; Holland, John D. (2014). <a rel="nofollow" class="external text" href="https://doi.org/10.22191%2Fneha%2Fvol43%2Fiss1%2F10">"Gunflints and Musket Balls: Implications for the Occupational History of the Eaton Site and the Niagara Frontier"</a>. <i>Northeast Historical Archaeology</i>. <b>43</b> (1): <span class="nowrap">189–</span>205. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.22191%2Fneha%2Fvol43%2Fiss1%2F10">10.22191/neha/vol43/iss1/10</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Northeast+Historical+Archaeology&rft.atitle=Gunflints+and+Musket+Balls%3A+Implications+for+the+Occupational+History+of+the+Eaton+Site+and+the+Niagara+Frontier&rft.volume=43&rft.issue=1&rft.pages=%3Cspan+class%3D%22nowrap%22%3E189-%3C%2Fspan%3E205&rft.date=2014&rft_id=info%3Adoi%2F10.22191%2Fneha%2Fvol43%2Fiss1%2F10&rft.aulast=Roets&rft.aufirst=Michael&rft.au=Engelbrecht%2C+William&rft.au=Holland%2C+John+D.&rft_id=https%3A%2F%2Fdoi.org%2F10.22191%252Fneha%252Fvol43%252Fiss1%252F10&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-60"><span class="mw-cite-backlink"><b><a href="#cite_ref-60">^</a></b></span> <span class="reference-text">Terry R. West. "Geology Applied to Engineering," Waveland Press, 1995 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/1577666550" title="Special:BookSources/1577666550">1577666550</a></span> </li> <li id="cite_note-FOOTNOTEBatesJackson1984"Flint"-61"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBatesJackson1984"Flint"_61-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBatesJackson1984">Bates & Jackson 1984</a>, "Flint".</span> </li> <li id="cite_note-62"><span class="mw-cite-backlink"><b><a href="#cite_ref-62">^</a></b></span> <span class="reference-text">George R. Rapp, "Archaeomineralogy", 2002. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/3-540-42579-9" title="Special:BookSources/3-540-42579-9">3-540-42579-9</a></span> </li> <li id="cite_note-63"><span class="mw-cite-backlink"><b><a href="#cite_ref-63">^</a></b></span> <span class="reference-text">Barbara E. Luedtke, "The Identification of Sources of Chert Artifacts", American Antiquity, Vol. 44, No. 4 (Oct., 1979), 744–757.</span> </li> <li id="cite_note-64"><span class="mw-cite-backlink"><b><a href="#cite_ref-64">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFLuedtke1992" class="citation book cs1">Luedtke, Barbara E. (1992). <a rel="nofollow" class="external text" href="https://escholarship.org/uc/item/7j8387sj"><i>An archaeologist's guide to chert and flint</i></a>. Los Angeles: Institute of Archaeology, University of California. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-917956-75-3" title="Special:BookSources/0-917956-75-3"><bdi>0-917956-75-3</bdi></a><span class="reference-accessdate">. Retrieved <span class="nowrap">8 October</span> 2020</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=An+archaeologist%27s+guide+to+chert+and+flint&rft.place=Los+Angeles&rft.pub=Institute+of+Archaeology%2C+University+of+California&rft.date=1992&rft.isbn=0-917956-75-3&rft.aulast=Luedtke&rft.aufirst=Barbara+E.&rft_id=https%3A%2F%2Fescholarship.org%2Fuc%2Fitem%2F7j8387sj&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTEBatesJackson1984"Jasper"-65"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBatesJackson1984"Jasper"_65-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBatesJackson1984">Bates & Jackson 1984</a>, "Jasper".</span> </li> <li id="cite_note-66"><span class="mw-cite-backlink"><b><a href="#cite_ref-66">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFKleinHurlbut1993" class="citation book cs1">Klein, Cornelis; Hurlbut, Cornelius S. Jr. (1993). <i>Manual of mineralogy : (after James D. Dana)</i> (21st ed.). New York: Wiley. p. 529. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/047157452X" title="Special:BookSources/047157452X"><bdi>047157452X</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Manual+of+mineralogy+%3A+%28after+James+D.+Dana%29&rft.place=New+York&rft.pages=529&rft.edition=21st&rft.pub=Wiley&rft.date=1993&rft.isbn=047157452X&rft.aulast=Klein&rft.aufirst=Cornelis&rft.au=Hurlbut%2C+Cornelius+S.+Jr.&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTEKleinHurlbut1993529-67"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEKleinHurlbut1993529_67-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFKleinHurlbut1993">Klein & Hurlbut 1993</a>, p. 529.</span> </li> <li id="cite_note-68"><span class="mw-cite-backlink"><b><a href="#cite_ref-68">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFLeetLowensteinRenautOwen2021" class="citation journal cs1">Leet, Kennie; Lowenstein, Tim K.; Renaut, Robin W.; Owen, R. Bernhart; Cohen, Andrew (3 June 2021). "Labyrinth patterns in Magadi (Kenya) cherts: Evidence for early formation from siliceous gels". <i>Geology</i>. <b>49</b> (9): <span class="nowrap">1137–</span>1142. <a href="/wiki/Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2021Geo....49.1137L">2021Geo....49.1137L</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1130%2FG48771.1">10.1130/G48771.1</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:236292156">236292156</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Geology&rft.atitle=Labyrinth+patterns+in+Magadi+%28Kenya%29+cherts%3A+Evidence+for+early+formation+from+siliceous+gels&rft.volume=49&rft.issue=9&rft.pages=%3Cspan+class%3D%22nowrap%22%3E1137-%3C%2Fspan%3E1142&rft.date=2021-06-03&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A236292156%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1130%2FG48771.1&rft_id=info%3Abibcode%2F2021Geo....49.1137L&rft.aulast=Leet&rft.aufirst=Kennie&rft.au=Lowenstein%2C+Tim+K.&rft.au=Renaut%2C+Robin+W.&rft.au=Owen%2C+R.+Bernhart&rft.au=Cohen%2C+Andrew&rfr_id=info%3Asid%2Fen.wikipedia.org%3AChert" class="Z3988"></span></span> </li> <li id="cite_note-FOOTNOTEBoggs2006207,_214-69"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBoggs2006207,_214_69-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBoggs2006">Boggs 2006</a>, pp. 207, 214.</span> </li> <li id="cite_note-FOOTNOTEBatesJackson1984"Tripoli"-70"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBatesJackson1984"Tripoli"_70-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBatesJackson1984">Bates & Jackson 1984</a>, "Tripoli".</span> </li> <li id="cite_note-FOOTNOTEBatesJackson1984"Mozarkite"-71"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBatesJackson1984"Mozarkite"_71-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBatesJackson1984">Bates & Jackson 1984</a>, "Mozarkite".</span> </li> <li id="cite_note-FOOTNOTEBatesJackson1984-72"><span class="mw-cite-backlink"><b><a href="#cite_ref-FOOTNOTEBatesJackson1984_72-0">^</a></b></span> <span class="reference-text"><a href="#CITEREFBatesJackson1984">Bates & Jackson 1984</a>.</span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a 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alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/40px-Commons-logo.svg.png" decoding="async" width="30" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/60px-Commons-logo.svg.png 1.5x" data-file-width="1024" data-file-height="1376" /></a></span></div> <div class="side-box-text plainlist">Wikimedia Commons has media related to <span style="font-weight: bold; font-style: italic;"><a href="https://commons.wikimedia.org/wiki/Category:Chert" class="extiw" title="commons:Category:Chert">Chert</a></span>.</div></div> </div> <ul><li><a rel="nofollow" class="external text" href="http://www.globalcommunity.org/wtt/walk_photos/3200.htm">Photo & note re: Fig Tree Formation</a></li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20050526080728/http://www2.bc.edu/~strother/GE_146/labs/lab7/Archaean.html">Microphotographs of Fig Tree fossils</a></li> <li>Schopf, J.W. 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style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Chalcedony" title="Chalcedony">Chalcedony</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Agate" title="Agate">Agate</a></li> <li><a href="/wiki/Carnelian" title="Carnelian">Carnelian</a></li> <li><a href="/wiki/Chrome_chalcedony" title="Chrome chalcedony">Chrome chalcedony</a></li> <li><a href="/wiki/Chrysoprase" title="Chrysoprase">Chrysoprase</a></li> <li><a href="/wiki/Heliotrope_(mineral)" title="Heliotrope (mineral)">Heliotrope</a></li> <li><a href="/wiki/Moss_agate" title="Moss agate">Moss agate</a></li> <li><a href="/wiki/Onyx" title="Onyx">Onyx</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Opal" 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title="Edit this template">e</abbr></a></li></ul></div><div id="Types_of_rocks88" style="font-size:114%;margin:0 4em">Types of rocks</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Igneous_rock" title="Igneous rock">Igneous rock</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Adakite" title="Adakite">Adakite</a></li> <li><a href="/wiki/Alkali_feldspar_granite" title="Alkali feldspar granite">Alkali feldspar granite</a></li> <li><a href="/wiki/Andesite" title="Andesite">Andesite</a></li> <li><a href="/wiki/Anorthosite" title="Anorthosite">Anorthosite</a></li> <li><a href="/wiki/Aplite" title="Aplite">Aplite</a></li> <li><a href="/wiki/Basalt" title="Basalt">Basalt</a> <ul><li><a href="/wiki/Alkali_basalt" title="Alkali basalt">Alkali basalt</a></li> <li><a href="/wiki/Picrite_basalt" title="Picrite basalt">Picrite basalt</a></li></ul></li> <li><a href="/wiki/Basaltic_trachyandesite" class="mw-redirect" title="Basaltic trachyandesite">Basaltic trachyandesite</a> <ul><li><a href="/wiki/Mugearite" title="Mugearite">Mugearite</a></li> <li><a href="/wiki/Shoshonite" title="Shoshonite">Shoshonite</a></li></ul></li> <li><a href="/wiki/Basanite" title="Basanite">Basanite</a></li> <li><a href="/wiki/Blairmorite" title="Blairmorite">Blairmorite</a></li> <li><a href="/wiki/Boninite" title="Boninite">Boninite</a></li> <li><a href="/wiki/Carbonatite" title="Carbonatite">Carbonatite</a></li> <li><a href="/wiki/Charnockite" title="Charnockite">Charnockite</a> <ul><li><a href="/wiki/Enderbite" title="Enderbite">Enderbite</a></li></ul></li> <li><a href="/wiki/Dacite" title="Dacite">Dacite</a></li> <li><a href="/wiki/Diabase" title="Diabase">Diabase</a></li> <li><a href="/wiki/Diorite" title="Diorite">Diorite</a> <ul><li><a href="/wiki/Napoleonite" title="Napoleonite">Napoleonite</a></li></ul></li> <li><a href="/wiki/Dunite" title="Dunite">Dunite</a></li> <li><a href="/wiki/Essexite" title="Essexite">Essexite</a></li> <li><a href="/wiki/Foidolite" title="Foidolite">Foidolite</a></li> <li><a href="/wiki/Gabbro" title="Gabbro">Gabbro</a></li> <li><a href="/wiki/Granite" title="Granite">Granite</a></li> <li><a href="/wiki/Granodiorite" title="Granodiorite">Granodiorite</a></li> <li><a href="/wiki/Granophyre" title="Granophyre">Granophyre</a></li> <li><a href="/wiki/Harzburgite" title="Harzburgite">Harzburgite</a></li> <li><a href="/wiki/Hornblendite" title="Hornblendite">Hornblendite</a></li> <li><a href="/wiki/Hyaloclastite" title="Hyaloclastite">Hyaloclastite</a></li> <li><a href="/wiki/Icelandite" title="Icelandite">Icelandite</a></li> <li><a href="/wiki/Ignimbrite" title="Ignimbrite">Ignimbrite</a></li> <li><a href="/wiki/Ijolite" title="Ijolite">Ijolite</a></li> <li><a href="/wiki/Kimberlite" title="Kimberlite">Kimberlite</a></li> <li><a href="/wiki/Komatiite" title="Komatiite">Komatiite</a></li> <li><a href="/wiki/Lamproite" title="Lamproite">Lamproite</a></li> <li><a href="/wiki/Lamprophyre" title="Lamprophyre">Lamprophyre</a></li> <li><a href="/wiki/Latite" title="Latite">Latite</a></li> <li><a href="/wiki/Lherzolite" title="Lherzolite">Lherzolite</a></li> <li><a href="/wiki/Monzogranite" title="Monzogranite">Monzogranite</a></li> <li><a href="/wiki/Monzonite" title="Monzonite">Monzonite</a></li> <li><a href="/wiki/Nepheline_syenite" title="Nepheline syenite">Nepheline syenite</a></li> <li><a href="/wiki/Nephelinite" title="Nephelinite">Nephelinite</a></li> <li><a href="/wiki/Norite" title="Norite">Norite</a></li> <li><a href="/wiki/Obsidian" title="Obsidian">Obsidian</a></li> <li><a href="/wiki/Pegmatite" title="Pegmatite">Pegmatite</a></li> <li><a href="/wiki/Peridotite" title="Peridotite">Peridotite</a></li> <li><a href="/wiki/Phonolite" title="Phonolite">Phonolite</a></li> <li><a href="/wiki/Phonotephrite" title="Phonotephrite">Phonotephrite</a></li> <li><a href="/wiki/Porphyry_(geology)" title="Porphyry (geology)">Porphyry</a></li> <li><a href="/wiki/Pumice" title="Pumice">Pumice</a></li> <li><a href="/wiki/Pyroxenite" title="Pyroxenite">Pyroxenite</a></li> <li><a href="/wiki/Quartz_diorite" title="Quartz diorite">Quartz diorite</a></li> <li><a href="/wiki/Quartz_monzonite" title="Quartz monzonite">Quartz monzonite</a></li> <li><a href="/wiki/Quartzolite" title="Quartzolite">Quartzolite</a></li> <li><a href="/wiki/Rhyodacite" title="Rhyodacite">Rhyodacite</a></li> <li><a href="/wiki/Rhyolite" title="Rhyolite">Rhyolite</a> <ul><li><a href="/wiki/Comendite" title="Comendite">Comendite</a></li> <li><a href="/wiki/Pantellerite" title="Pantellerite">Pantellerite</a></li></ul></li> <li><a href="/wiki/Scoria" title="Scoria">Scoria</a></li> <li><a href="/wiki/Shonkinite" title="Shonkinite">Shonkinite</a></li> <li><a href="/wiki/Sovite" title="Sovite">Sovite</a></li> <li><a href="/wiki/Syenite" title="Syenite">Syenite</a></li> <li><a href="/wiki/Tachylyte" class="mw-redirect" title="Tachylyte">Tachylyte</a></li> <li><a href="/wiki/Tephriphonolite" title="Tephriphonolite">Tephriphonolite</a></li> <li><a href="/wiki/Tephrite" title="Tephrite">Tephrite</a></li> <li><a href="/wiki/Tonalite" title="Tonalite">Tonalite</a></li> <li><a href="/wiki/Trachyandesite" title="Trachyandesite">Trachyandesite</a> <ul><li><a href="/wiki/Benmoreite" title="Benmoreite">Benmoreite</a></li></ul></li> <li><a href="/wiki/Trachybasalt" title="Trachybasalt">Trachybasalt</a> <ul><li><a href="/wiki/Hawaiite" title="Hawaiite">Hawaiite</a></li></ul></li> <li><a href="/wiki/Trachyte" title="Trachyte">Trachyte</a></li> <li><a href="/wiki/Troctolite" title="Troctolite">Troctolite</a></li> <li><a href="/wiki/Trondhjemite" title="Trondhjemite">Trondhjemite</a></li> <li><a href="/wiki/Tuff" title="Tuff">Tuff</a></li> <li><a href="/wiki/Websterite" title="Websterite">Websterite</a></li> <li><a href="/wiki/Wehrlite" title="Wehrlite">Wehrlite</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Sedimentary_rock" title="Sedimentary rock">Sedimentary rock</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Argillite" title="Argillite">Argillite</a></li> <li><a href="/wiki/Arkose" title="Arkose">Arkose</a></li> <li><a href="/wiki/Banded_iron_formation" title="Banded iron formation">Banded iron formation</a></li> <li><a href="/wiki/Breccia" title="Breccia">Breccia</a></li> <li><a href="/wiki/Calcarenite" title="Calcarenite">Calcarenite</a></li> <li><a href="/wiki/Chalk" title="Chalk">Chalk</a></li> <li><a class="mw-selflink selflink">Chert</a></li> <li><a href="/wiki/Claystone" class="mw-redirect" title="Claystone">Claystone</a></li> <li><a href="/wiki/Coal" title="Coal">Coal</a></li> <li><a href="/wiki/Conglomerate_(geology)" title="Conglomerate (geology)">Conglomerate</a></li> <li><a href="/wiki/Coquina" title="Coquina">Coquina</a></li> <li><a href="/wiki/Diamictite" title="Diamictite">Diamictite</a></li> <li><a href="/wiki/Diatomite" class="mw-redirect" title="Diatomite">Diatomite</a></li> <li><a href="/wiki/Dolomite_(rock)" title="Dolomite (rock)">Dolomite</a></li> <li><a href="/wiki/Evaporite" title="Evaporite">Evaporite</a></li> <li><a href="/wiki/Flint" title="Flint">Flint</a></li> <li><a href="/wiki/Geyserite" title="Geyserite">Geyserite</a></li> <li><a href="/wiki/Greywacke" title="Greywacke">Greywacke</a></li> <li><a href="/wiki/Gritstone" title="Gritstone">Gritstone</a></li> <li><a href="/wiki/Itacolumite" title="Itacolumite">Itacolumite</a></li> <li><a href="/wiki/Jaspillite" title="Jaspillite">Jaspillite</a></li> <li><a href="/wiki/Laterite" title="Laterite">Laterite</a></li> <li><a href="/wiki/Lignite" title="Lignite">Lignite</a></li> <li><a href="/wiki/Limestone" title="Limestone">Limestone</a></li> <li><a href="/wiki/Lumachelle" title="Lumachelle">Lumachelle</a></li> <li><a href="/wiki/Marl" title="Marl">Marl</a></li> <li><a href="/wiki/Mudstone" title="Mudstone">Mudstone</a></li> <li><a href="/wiki/Oil_shale" title="Oil shale">Oil shale</a></li> <li><a href="/wiki/Oolite" title="Oolite">Oolite</a></li> <li><a href="/wiki/Phosphorite" title="Phosphorite">Phosphorite</a></li> <li><a href="/wiki/Sandstone" title="Sandstone">Sandstone</a></li> <li><a href="/wiki/Shale" title="Shale">Shale</a></li> <li><a href="/wiki/Siltstone" title="Siltstone">Siltstone</a></li> <li><a href="/wiki/Sylvinite" title="Sylvinite">Sylvinite</a></li> <li><a href="/wiki/Tillite" class="mw-redirect" title="Tillite">Tillite</a></li> <li><a href="/wiki/Travertine" title="Travertine">Travertine</a></li> <li><a href="/wiki/Tufa" title="Tufa">Tufa</a></li> <li><a href="/wiki/Turbidite" title="Turbidite">Turbidite</a></li> <li><a href="/wiki/Varve" title="Varve">Varve</a></li> <li><a href="/wiki/Wackestone" title="Wackestone">Wackestone</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Metamorphic_rock" title="Metamorphic rock">Metamorphic rock</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Anthracite" title="Anthracite">Anthracite</a></li> <li><a href="/wiki/Amphibolite" title="Amphibolite">Amphibolite</a></li> <li><a href="/wiki/Blueschist" title="Blueschist">Blueschist</a></li> <li><a href="/wiki/Cataclasite" title="Cataclasite">Cataclasite</a></li> <li><a href="/wiki/Eclogite" title="Eclogite">Eclogite</a></li> <li><a href="/wiki/Gneiss" title="Gneiss">Gneiss</a></li> <li><a href="/wiki/Granulite" title="Granulite">Granulite</a></li> <li><a href="/wiki/Greenschist" title="Greenschist">Greenschist</a></li> <li><a href="/wiki/Hornfels" title="Hornfels">Hornfels</a> <ul><li><a href="/wiki/Calcflinta" title="Calcflinta">Calcflinta</a></li></ul></li> <li><a href="/wiki/Itabirite" title="Itabirite">Itabirite</a></li> <li><a href="/wiki/Litchfieldite" title="Litchfieldite">Litchfieldite</a></li> <li><a href="/wiki/Marble" title="Marble">Marble</a></li> <li><a href="/wiki/Migmatite" title="Migmatite">Migmatite</a></li> <li><a href="/wiki/Mylonite" title="Mylonite">Mylonite</a></li> <li><a href="/wiki/Metapelite" class="mw-redirect" title="Metapelite">Metapelite</a></li> <li><a href="/w/index.php?title=Metapsammite&action=edit&redlink=1" class="new" title="Metapsammite (page does not exist)">Metapsammite</a></li> <li><a href="/wiki/Phyllite" title="Phyllite">Phyllite</a></li> <li><a href="/wiki/Pseudotachylite" class="mw-redirect" title="Pseudotachylite">Pseudotachylite</a></li> <li><a href="/wiki/Quartzite" title="Quartzite">Quartzite</a></li> <li><a href="/wiki/Schist" title="Schist">Schist</a></li> <li><a href="/wiki/Serpentinite" title="Serpentinite">Serpentinite</a></li> <li><a href="/wiki/Skarn" title="Skarn">Skarn</a></li> <li><a href="/wiki/Slate" title="Slate">Slate</a></li> <li><a href="/wiki/Suevite" title="Suevite">Suevite</a></li> <li><a href="/wiki/Talc_carbonate" title="Talc carbonate">Talc carbonate</a> <ul><li><a href="/wiki/Soapstone" title="Soapstone">Soapstone</a></li></ul></li> <li><a href="/wiki/Tectonite" title="Tectonite">Tectonite</a></li> <li><a href="/wiki/Whiteschist" title="Whiteschist">Whiteschist</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Specific varieties</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Adamellite" class="mw-redirect" title="Adamellite">Adamellite</a></li> <li><a href="/wiki/Appinite" title="Appinite">Appinite</a></li> <li><a href="/wiki/Aphanite" title="Aphanite">Aphanite</a></li> <li><a href="/wiki/Borolanite" title="Borolanite">Borolanite</a></li> <li><a href="/wiki/Larvikite" title="Larvikite">Blue Granite</a></li> <li><a href="/wiki/Epidosite" title="Epidosite">Epidosite</a></li> <li><a href="/wiki/Felsite" title="Felsite">Felsite</a></li> <li><a href="/wiki/Flint" title="Flint">Flint</a></li> <li><a href="/wiki/Ganister" title="Ganister">Ganister</a></li> <li><a href="/wiki/Gossan" title="Gossan">Gossan</a></li> <li><a href="/wiki/Hyaloclastite" title="Hyaloclastite">Hyaloclastite</a></li> <li><a href="/wiki/Ijolite" title="Ijolite">Ijolite</a></li> <li><a href="/wiki/Jadeitite" title="Jadeitite">Jadeitite</a></li> <li><a href="/wiki/Jasperoid" title="Jasperoid">Jasperoid</a></li> <li><a href="/wiki/Kenyte" title="Kenyte">Kenyte</a></li> <li><a href="/wiki/Lapis_lazuli" title="Lapis lazuli">Lapis lazuli</a></li> <li><a href="/wiki/Larvikite" title="Larvikite">Larvikite</a></li> <li><a href="/wiki/Litchfieldite" title="Litchfieldite">Litchfieldite</a></li> <li><a href="/wiki/Llanite" title="Llanite">Llanite</a></li> <li><a href="/wiki/Luxullianite" title="Luxullianite">Luxullianite</a></li> <li><a href="/wiki/Mangerite" title="Mangerite">Mangerite</a></li> <li><a href="/wiki/Novaculite" title="Novaculite">Novaculite</a></li> <li><a href="/wiki/Pietersite" title="Pietersite">Pietersite</a></li> <li><a href="/wiki/Pyrolite" title="Pyrolite">Pyrolite</a></li> <li><a href="/wiki/Rapakivi_granite" title="Rapakivi granite">Rapakivi granite</a></li> <li><a href="/wiki/Rhomb_porphyry" class="mw-redirect" title="Rhomb porphyry">Rhomb porphyry</a></li> <li><a href="/wiki/Rodingite" title="Rodingite">Rodingite</a></li> <li><a href="/wiki/Shonkinite" title="Shonkinite">Shonkinite</a></li> <li><a href="/wiki/Taconite" title="Taconite">Taconite</a></li> <li><a href="/wiki/Tachylite" title="Tachylite">Tachylite</a></li> <li><a href="/wiki/Teschenite" title="Teschenite">Teschenite</a></li> <li><a href="/wiki/Theralite" title="Theralite">Theralite</a></li> <li><a href="/wiki/Unakite" title="Unakite">Unakite</a></li> <li><a href="/wiki/Variolite" title="Variolite">Variolite</a></li> <li><a href="/wiki/Wad_(mineral)" title="Wad (mineral)">Wad</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235" /></div><div role="navigation" class="navbox authority-control" aria-label="Navbox473" style="padding:3px"><table class="nowraplinks hlist navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Help:Authority_control" title="Help:Authority control">Authority control databases</a>: National <span class="mw-valign-text-top noprint" typeof="mw:File/Frameless"><a href="https://www.wikidata.org/wiki/Q1070438#identifiers" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" 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<script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.eqiad.main-78bdfcd464-r2fbd","wgBackendResponseTime":232,"wgPageParseReport":{"limitreport":{"cputime":"1.397","walltime":"1.719","ppvisitednodes":{"value":9313,"limit":1000000},"postexpandincludesize":{"value":123681,"limit":2097152},"templateargumentsize":{"value":6523,"limit":2097152},"expansiondepth":{"value":16,"limit":100},"expensivefunctioncount":{"value":5,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":182089,"limit":5000000},"entityaccesscount":{"value":1,"limit":400},"timingprofile":["100.00% 1529.504 1 -total"," 27.51% 420.785 1 Template:Reflist"," 17.86% 273.116 68 Template:Sfn"," 16.70% 255.436 20 Template:Cite_journal"," 15.39% 235.323 8 Template:Annotated_link"," 9.01% 137.880 3 Template:Navbox"," 7.88% 120.589 1 Template:Silica_minerals"," 7.84% 119.919 1 Template:Commons_category"," 7.21% 110.335 1 Template:Sister_project"," 6.81% 104.108 1 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1,\n [\"CITEREFRoetsEngelbrechtHolland2014\"] = 1,\n [\"CITEREFSchopf1968\"] = 1,\n [\"CITEREFSchopf2001\"] = 1,\n [\"CITEREFSmithHuckell2005\"] = 1,\n [\"CITEREFThurston1972\"] = 1,\n [\"CITEREFWaceyEiloartSaunders2019\"] = 1,\n [\"CITEREFWaceySaundersKongBrasier2016\"] = 1,\n}\ntemplate_list = table#1 {\n [\"Annotated link\"] = 8,\n [\"Authority control\"] = 1,\n [\"Cite book\"] = 8,\n [\"Cite journal\"] = 20,\n [\"Cite web\"] = 2,\n [\"Commons category\"] = 1,\n [\"Convert\"] = 5,\n [\"For multi\"] = 1,\n [\"IPAc-en\"] = 1,\n [\"ISBN\"] = 5,\n [\"Infobox rock\"] = 1,\n [\"Reflist\"] = 1,\n [\"Rock type\"] = 1,\n [\"Sfn\"] = 68,\n [\"Short description\"] = 1,\n [\"Silica minerals\"] = 1,\n [\"Use dmy dates\"] = 1,\n [\"Webarchive\"] = 2,\n}\narticle_whitelist = table#1 {\n}\nciteref_patterns = table#1 {\n}\n"},"cachereport":{"origin":"mw-web.eqiad.main-8669bc5c8-kkv22","timestamp":"20250318155636","ttl":2592000,"transientcontent":false}}});});</script> <script 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