Rock Identifier
Ammonite (Ammonoidea) — fossil
fossil

Ammonite

Ammonoidea

AI-generated identification · may be incorrect

Hardness 3.5 to 4 on Mohs scale, varies in color from brown to grey, pearly or earthy luster, distinctive coiled chambered shell structure.

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Physical properties

Hardness 3.5 to 4 on Mohs scale, varies in color from brown to grey, pearly or earthy luster, distinctive coiled chambered shell structure.

Formation & geological history

Formed through the fossilization of marine mollusk shells from the Devonian to Cretaceous periods, approximately 400 to 66 million years ago.

Uses & applications

Used primarily as decorative items, jewelry, and prized specimens for fossil and mineral collections.

Geological facts

Ammonites are extinct marine animals closely related to modern octopuses and squids rather than to chambered nautiluses.

Field identification & locations

Easily identified in the field by their characteristic planispiral shell shape and complex suture patterns. Found worldwide in marine sedimentary rocks.

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Weathered fossil bone fragment (identification uncertain)

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