Rock Identifier
Fossilized gastropod shell (Calcitic or aragonitic gastropod fossil; likely Mollusca, Gastropoda) — fossil
fossil

Fossilized gastropod shell

Calcitic or aragonitic gastropod fossil; likely Mollusca, Gastropoda

AI-generated identification · may be incorrect

Brown, spiral shell fragment with layered whorls and a dull to weakly glossy surface; original shell is calcium carbonate (Mohs 3–4), commonly replaced or impregnated by calcite. Curved growth lines and coiling distinguish it from ordinary stone.

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Physical properties

Brown, spiral shell fragment with layered whorls and a dull to weakly glossy surface; original shell is calcium carbonate (Mohs 3–4), commonly replaced or impregnated by calcite. Curved growth lines and coiling distinguish it from ordinary stone.

Formation & geological history

Formed when a marine or freshwater snail shell was buried in sediment and mineralized during diagenesis, often over thousands to millions of years. Exact age and species require locality and microscopic examination.

Uses & applications

Primarily a collecting, educational, and decorative specimen; uncommon or well-preserved examples may be used in paleontology displays.

Geological facts

Gastropods are among the most diverse fossil groups, and their coiled shells can preserve environmental and evolutionary information. The pictured specimen appears weathered and incomplete.

Field identification & locations

Look for a continuous spiral, whorls, aperture or shell ribs, and carbonate reaction with dilute hydrochloric acid; avoid confusing it with a concretion or modern shell. Fossil gastropods occur worldwide in limestone and other sedimentary rocks.

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