fossil

Fossilized bivalve shell

Indeterminate fossil mollusk; likely a brachiopod or bivalve, originally calcite/aragonite (CaCO₃)

AI-generated identification · may be incorrect

Small, fan- to triangular-shaped shell impression/specimen with ribs and a dark, weathered surface; hardness about 3–4 if calcitic, with dull to pearly luster and weak cleavage. Exact identification is limited by the blurred image and apparent partial preservation.

Identified August 16, 2026More fossil →

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Physical properties

Formation & geological history

Formed when a marine mollusk was buried in sediment and its shell mineralized, compacted, or left as a mold/cast; age cannot be determined from the photograph, but such fossils range from Paleozoic to Recent deposits.

Uses & applications

Primarily used for education, decoration, and collecting; complete, well-preserved examples may be sold as display fossils.

Geological facts

The visible radial ornamentation and symmetrical outline are typical of shelled marine invertebrates. A shell fossil is geological material even when polished, coated, or partly reconstructed.

Field identification & locations

Common in marine limestone, shale, and sandstone. Look for bilateral symmetry, growth lines, hinge features, and a rock-like replacement; dilute acid may fizz on exposed calcite, but avoid testing valuable specimens.