Ammonite fossil (Agatized)
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/photos/26782864@N00">William Warby</a> from London, England (CC BY 2.0)
Mineral NameAmmonite fossil (Agatized)
Chemical FormulaSiO2
Mohs Hardness6.5
Crystal Systemamorphous
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.6
Colorsyellow, orange, brown, white
Transparencytranslucent
Type LocalityNormandy, France
Mineral GroupSilicates
Usesjewelry, collector's item, decorative
Associated Mineralscalcite, pyrite, quartz
Rarityuncommon
Description
This image displays a polished cross-section of an ammonite fossil, showcasing its intricate spiral chambers filled with translucent, golden-yellow to orange agate, highlighted by white and brown mineral accents.
Geological Context
Ammonites were marine cephalopods that thrived during the Mesozoic Era. Their shells were preserved as fossils in marine sedimentary rocks, with the internal chambers often filled by silica (forming agate) or calcite through permineralization over millions of years.
