fossil

Fossilized bivalve shell

Bivalvia (likely a venerid or similar clam); shell composed mainly of CaCO₃ as aragonite/calcite

AI-generated identification · may be incorrect

Hardness about 3–4 Mohs; glossy dark brown shell with cream concentric growth bands, strong radial symmetry, and layered nacreous structure. It is a biological carbonate fossil rather than a crystalline rock.

Identified August 8, 2026More fossil →

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Physical properties

Formation & geological history

Formed by a marine bivalve that secreted a calcium-carbonate shell; burial and mineral preservation may have occurred from the Cenozoic to Recent, but age cannot be determined from the image alone.

Uses & applications

Primarily used for education, paleontology, and collecting; complete specimens may be displayed or used decoratively, but this form has little industrial value.

Geological facts

The concentric bands record episodic growth and environmental changes. The visible hinge/apical area and rounded triangular profile are characteristic of a clam-type shell.

Field identification & locations

Identify by the paired-valve shape, concentric growth lines, carbonate composition, and absence of rock-like granular texture; common in marine sediments and beaches worldwide. Avoid acids, which can etch carbonate shell.