sedimentary
Fossilized Brachiopod
Brachiopoda (likely Order Spiriferida or Productida)
Hardness: 3-4 (calcite-based); Color: Gray to olive-brown; Luster: Dull/earthy; Structure: Bivalved shell with bilateral symmetry across the valve; Cleavage: None (fossilized structure).
- Hardness
- 3-4 (calcite-based)
- Color
- Gray to olive-brown
- Luster
- Dull/earthy
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Physical properties
Hardness: 3-4 (calcite-based); Color: Gray to olive-brown; Luster: Dull/earthy; Structure: Bivalved shell with bilateral symmetry across the valve; Cleavage: None (fossilized structure).
Formation & geological history
Formed during the Paleozoic era (approx. 250-500 million years ago) through the permineralization of marine organisms in shallow seafloor sediments.
Uses & applications
Primarily used for scientific study of evolutionary history, educational purposes, and as a collector's hobby item.
Geological facts
Brachiopods are often called 'lamp shells' because their shape resembles ancient oil lamps. They have survived all five major mass extinctions in Earth's history.
Field identification & locations
Identified by their U-shaped or fan-shaped ridged valves and a hinge line. They are commonly found in limestone or shale outcrops in the Midwestern United States and UK.
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