Rock Identifier
Ammonite Fossil in Matrix (Ammonoidea subclass embedded in sedimentary shale) — fossil
fossil

Ammonite Fossil in Matrix

Ammonoidea subclass embedded in sedimentary shale

AI-generated identification · may be incorrect

Mohs hardness around 3-4 for the fossil, gray shale matrix. Color ranges from white/beige for the fossil to gray for the rock. Luster is dull to pearly.

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Physical properties

Mohs hardness around 3-4 for the fossil, gray shale matrix. Color ranges from white/beige for the fossil to gray for the rock. Luster is dull to pearly.

Formation & geological history

Formed during the Mesozoic era when cephalopods died and settled on anoxic sea floors, eventually becoming permineralized within accumulating sediment layers over millions of years.

Uses & applications

Prized by fossil collectors, educational displays, and sometimes used in decorative lapidary work or jewelry.

Geological facts

Ammonites are extinct marine mollusk relatives of modern squids and octopuses, serving as excellent index fossils for dating geological strata.

Field identification & locations

Identify by the distinctive coiled spiral shell embedded in fine-grained sedimentary rock. Commonly found in marine shale and limestone deposits worldwide.

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Phylum Echinodermata, Class Crinoidea

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Fossiliferous limestone (likely a crinoidal or shell-fragment limestone) (Bioclastic limestone, composed chiefly of calcite (CaCO₃)) — sedimentary

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

sedimentary
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Porous limestone pebble

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sedimentary
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Weathered fossil bone fragment (identification uncertain)

Fossilized bone; exact taxon and mineral composition cannot be determined from the image

fossil