fossil

Fossil scallop shell

Bivalve mollusk shell, likely family Pectinidae; primarily calcite (CaCO₃)

AI-generated identification · may be incorrect

Hardness about 3 Mohs; cream to pale tan with radiating ribs, matte to pearly luster, and layered shell structure. It has bilateral symmetry and a fan-shaped, ribbed form rather than a crystalline texture.

Identified September 16, 2026More fossil →

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Physical properties

Formation & geological history

A biological shell formed by a marine bivalve, later buried and preserved; mineral replacement or recrystallization may have occurred. Its exact geological age cannot be determined from the image and may range from modern shell to fossil, depending on preservation and locality.

Uses & applications

Used as a decorative specimen, teaching material, craft item, or collectible; calcitic shell material is not typically used as gemstone or construction stone.

Geological facts

The radiating ribs strengthened the shell against wave and predation forces. Pectinid shells are common marine fossils and are often recognizable even when partially mineralized.

Field identification & locations

Identify it by the fan shape, strong radial ribs, and two-valved bivalve symmetry; test cautiously with dilute acid, which effervesces on calcite. Common in modern beaches and marine sedimentary rocks worldwide.