sedimentary
Fossilized Bivalve Shell
Bivalvia (fossil specimen)
Hardness: 3-3.5 (Calcite); Color: Off-white, grey, or tan; Luster: Dull to chalky; Structure: Concentric growth lines; Composition: Calcium carbonate (Calcite/Aragonite).
- Hardness
- 3-3
- Color
- Off-white, grey, or tan
- Luster
- Dull to chalky
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Physical properties
Hardness: 3-3.5 (Calcite); Color: Off-white, grey, or tan; Luster: Dull to chalky; Structure: Concentric growth lines; Composition: Calcium carbonate (Calcite/Aragonite).
Formation & geological history
Formed when a marine or freshwater mollusk was buried in sediment. Over time, mineral replacement or permineralization occurs. These can date from the Paleozoic to the Holocene.
Uses & applications
Paleontological study, educational tools, decorative items, and amateur fossil collecting.
Geological facts
The tiny holes visible on the surface are likely bioerosion marks caused by boring organisms like sponges (Cliona) or predatory gastropods after the mollusk died.
Field identification & locations
Identified by symmetrical valves and visible growth rings. Commonly found in limestone outcrops, riverbeds, and coastal sedimentary formations.
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