Ammonite Fossil
Image: <a href="//commons.wikimedia.org/wiki/User:Jsnueva1022" title="User:Jsnueva1022">Julan Shirwod Nueva</a> (CC BY-SA 4.0)
Mineral NameAmmonite Fossil
Chemical FormulaCaCO3
Mohs Hardness3
Crystal Systemorthorhombic
Lusterdull
Streak Colorwhite to light grey
Cleavageindistinct
Fractureuneven
Specific Gravity2.7
Colorsdark grey, black, brown
Transparencyopaque
Type LocalityColasi Pt., Mansalay, Oriental Mindoro, Philippines
Mineral GroupCarbonates (biogenic)
Usesscientific study, education, collector's item, decorative
Associated Mineralscalcite, quartz, pyrite, clay minerals
Rarityuncommon
Description
A large, dark grey, spiral-shelled ammonite fossil, exhibiting prominent ribbing and a well-preserved coiled structure, displayed on a stand.
Geological Context
This fossil represents a marine cephalopod from the Middle Oxfordian Age (Jurassic period), found in sedimentary rocks, indicating deposition in an ancient marine environment approximately 160 million years ago.
