fossil

Fossilized bivalve shell fragment

Calcitic fossil shell, likely a pectinid or related bivalve; CaCO₃

AI-generated identification · may be incorrect

Hardness about 3 (calcite), brown to gray weathered surface, dull to waxy luster, dense fine-grained shell material, and curved layered structure with possible rib or hinge features. It is not confidently identifiable to genus from this single partial view.

Identified September 12, 2026More fossil →

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Physical properties

Formation & geological history

A marine mollusk shell was originally aragonitic or calcitic and became mineralized during burial, commonly through recrystallization to calcite. Its precise age and formation locality cannot be determined from the image.

Uses & applications

Primarily a collector, educational, or decorative specimen; fossil shells may also be used in paleontology and local geological displays, but not commonly in industry or jewelry.

Geological facts

The visible curvature, layered shell texture, and irregular broken edge favor fossil shell over an ordinary rock. Brown coloration likely reflects iron staining or burial-related mineral alteration.

Field identification & locations

Look for bilateral shell curvature, growth lines, ribs, hinge structures, and a distinctly layered interior; acid would fizz if calcitic, though testing may damage it. Fossil bivalves occur widely in marine sedimentary rocks worldwide.