sedimentary
Brachiopod Fossil
Rhynchonellida (Order)
Hardness: 3-4 (Calcite composition); Color: Tan/Grey; Luster: Dull/Earthy; Structure: Bilateral symmetry with radial ribbing (costae).
- Hardness
- 3-4 (Calcite composition)
- Color
- Tan/Grey
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3-4 (Calcite composition); Color: Tan/Grey; Luster: Dull/Earthy; Structure: Bilateral symmetry with radial ribbing (costae).
Formation & geological history
Formed via permineralization in marine sedimentary environments. These fossils typically date from the Paleozoic to Mesozoic eras, often hundreds of millions of years old.
Uses & applications
Scientific study (paleontology), educational tools, and hobbyist fossil collecting.
Geological facts
Unlike clams, which have left and right shells, brachiopods have 'top' and 'bottom' shells (valves) of different sizes. They are known as 'lamp shells' due to their resemblance to ancient oil lamps.
Field identification & locations
Identify by looking for radial ridges and a distinct 'beak' at the hinge. Found globally in limestone and shale deposits.
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