fossil

Fossilized shell fragment, likely bivalve

Bivalvia indet.; commonly preserved as calcite (CaCO₃) shell material

AI-generated identification · may be incorrect

Hardness about 3 (calcite), gray-brown to cream banding, dull to pearly luster, layered/coiled shell growth lines, and good cleavage in calcite. The ridged, laminated form strongly suggests a weathered marine shell rather than an igneous or metamorphic rock.

Identified September 7, 2026More fossil →

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Physical properties

Formation & geological history

A marine mollusk shell accumulated in sediment and was buried, lithified, and variably mineralized during diagenesis; its exact geological age cannot be determined from the image. Fossil shells commonly occur in limestone, shale, and sandstone.

Uses & applications

Primarily a collectible, teaching specimen, or decorative object; fossil shell material is not generally used for construction or jewelry unless exceptionally preserved or polished.

Geological facts

The visible concentric growth bands record episodic shell growth and environmental changes. Exact identification requires the opposite valve, hinge features, and locality information.

Field identification & locations

Look for consistent biological symmetry, growth lines, shell curvature, and replacement by calcite; acid may fizz, but testing can damage it. Common in marine sedimentary exposures worldwide, especially limestone formations.