fossil

Bivalve Fossil (Cockle shell)

Class Bivalvia (e.g., Anadara or Veneridae family)

Hardness: 3 (calcite); Color: white, cream, or grey; Luster: dull to pearly; Structure: bilateral symmetry between valves, radial ribbing; Composition: Calcium carbonate (calcite or aragonite).

Hardness: 3 (calcite)
Color: white, cream, or grey
Luster: dull to pearly

Identified July 13, 2026More fossil →

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Physical properties

Hardness: 3 (calcite); Color: white, cream, or grey; Luster: dull to pearly; Structure: bilateral symmetry between valves, radial ribbing; Composition: Calcium carbonate (calcite or aragonite).

Formation & geological history

Formed through the permineralization or replacement of a marine mollusk shell. These fossils are found in sedimentary rock layers ranging from the Paleozoic era to the Holocene, typically in ancient seabed environments.

Uses & applications

Used primarily for educational purposes, paleontological study, and collector display pieces. Small specimens are often used in decorative crafts.

Geological facts

Bivalves are one of the most successful groups of animals, surviving several mass extinctions. Their fossils are often used by geologists as index fossils to date sedimentary rock layers.

Field identification & locations

Look for distinct radial ridges and a hinged 'beak' (umbo). They are commonly found in limestone, shale, or sandstone coastal cliffs and quarries. Collectors should look for complete margins and original shell detail.

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