Fossil Bivalve Shell

Physical Properties

Hardness: 3-3.5 (Calcite/Aragonite); Color: Off-white to tan; Luster: Pearly to dull; Structure: Calcified biological shell; Cleavage: None; Specific Gravity: ~2.7

Formation & Geological History

Formed through the process of permineralization or replacement where biological calcium carbonate is preserved in marine sediments. Can range from the Paleozoic era to the Holocene.

Uses & Applications

Used for geological study, biological education, decorative items, and as a component of fossiliferous limestone used in construction.

Geological Facts

Bivalves are one of the most successful groups of mollusks. Their fossils are excellent paleoenvironmental indicators, telling scientists about ancient water depths and temperatures.

Field Identification & Locations

Identify by the symmetrical valves (shells), growth lines, and hinge structure. Commonly found in sedimentary rock outcrops (limestone/shale) and on beaches.

Identified on: 5/3/2026

Mode: Standard