Rock Identifier

fossil

Fossilized Oyster

Crassostrea gigas

AI-generated identification · may be incorrect

Hardness 3 to 4 on Mohs scale, grayish-brown color, dull to pearly luster, composed primarily of calcium carbonate in a calcitic and aragonitic shell structure.

Identified October 19, 2026More fossil →

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Physical properties

Hardness 3 to 4 on Mohs scale, grayish-brown color, dull to pearly luster, composed primarily of calcium carbonate in a calcitic and aragonitic shell structure.

Formation & geological history

Formed through the process of permineralization in shallow marine environments, dating back millions of years from the Mesozoic to Cenozoic eras.

Uses & applications

Valued primarily as a paleontological specimen, educational tool, and collector's item rather than for industrial use.

Geological facts

Fossilized oyster shells often preserve intricate growth lines and provide key insights into ancient marine ecosystems and past climate conditions.

Field identification & locations

Easily identified by its distinct layered shell morphology and rough exterior; commonly found in sedimentary limestone and clay formations worldwide.

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Other fossil specimens

Probable fossil-bearing rock or mineral concretion (Unidentified carbonate-rich concretion with a possible fossil inclusion) — fossil

Probable fossil-bearing rock or mineral concretion

Unidentified carbonate-rich concretion with a possible fossil inclusion

Likely fossil oyster shell (Fossilized bivalve shell; exact species cannot be identified from the image) — fossil

Likely fossil oyster shell

Fossilized bivalve shell; exact species cannot be identified from the image

Crinoid Stem Fossil in Matrix (Phylum Echinodermata, Class Crinoidea) — fossil

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

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)

Porous limestone pebble (Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image) — sedimentary

Porous limestone pebble

Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image

Fossil oyster shell (Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)) — fossil

Fossil oyster shell

Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)