sedimentary
Fossilized Brachiopod
Phylum Brachiopoda (Calcium Carbonate/Silica replacement)
Hardness: 3-3.5 (if calcite) or 7 (if silicified); Color: Tan, grey, or white; Luster: Dull to earthy; Structure: Bilateral symmetry with distinct growth lines and ribbing (costae).
- Hardness
- 3-3
- Color
- Tan, grey, or white
- Luster
- Dull to earthy
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Physical properties
Hardness: 3-3.5 (if calcite) or 7 (if silicified); Color: Tan, grey, or white; Luster: Dull to earthy; Structure: Bilateral symmetry with distinct growth lines and ribbing (costae).
Formation & geological history
Formed in ancient marine environments when the shells of lamp shells were buried in sediment and lithified over millions of years, commonly from the Paleozoic Era.
Uses & applications
Paleontological study, educational tools, and common items for fossil collectors.
Geological facts
Brachiopods are not mollusks, despite their appearance; they have a unique feeding organ called a lophophore. They have survived for over 500 million years.
Field identification & locations
Look for a clam-like shell with one valve larger than the other and distinctive radial ribbing. Commonly found in limestone outcrops and riverbeds in the Midwest and Appalachia.
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