fossil

Fossil oyster shell

Fossilized oyster (Bivalvia; exact genus and age cannot be determined from the image)

AI-generated identification · may be incorrect

Irregular, thick shell with pronounced concentric growth ridges and a pale gray-beige surface. Original shell is chiefly calcium carbonate (calcite or aragonite); hardness about 3 on Mohs, though fossilization may alter its composition. Luster dull to slightly pearly; crystal structure is not reliably visible.

Identified October 13, 2026More fossil →

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Physical properties

Formation & geological history

Formed as an oyster shell in a marine environment, then buried in sediment and preserved or mineralized over geologic time. The image does not provide enough context to determine its age or locality.

Uses & applications

Primarily collected for display and education; fossil oyster shells have little industrial or jewelry use.

Geological facts

Oysters cement themselves to surfaces and grow irregular shells, producing the distinctive layered, uneven form seen here.

Field identification & locations

Look for layered growth lines, a thick uneven shell, and a hinge or attachment area; these distinguish it from most mineral specimens. Common in marine sedimentary deposits worldwide. Typical loose specimens: about $5–$30, depending on size, preservation, and provenance.