sedimentary
Brachiopod Fossil in Limestone
Phylum Brachiopoda, Class Rhynchonellata
Hardness: 3 (limestone matrix); Color: Tan/Grey; Luster: Dull/Earthy; Structure: Symmetrical bivalved shell with ribbing; Cleavage: None; Specific Gravity: Approx 2.7
- Hardness
- 3 (limestone matrix)
- Color
- Tan/Grey
- Luster
- Dull/Earthy
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Physical properties
Hardness: 3 (limestone matrix); Color: Tan/Grey; Luster: Dull/Earthy; Structure: Symmetrical bivalved shell with ribbing; Cleavage: None; Specific Gravity: Approx 2.7
Formation & geological history
Formed in shallow marine environments during the Paleozoic or Mesozoic eras (approx. 50-500 million years ago) through the mineralization of marine shells within lime mud.
Uses & applications
Scientific study, educational tools, fossil collecting, and occasionally used in limestone production for construction.
Geological facts
Brachiopods are not clams; while they look like bivalve mollusks, they are their own distinct phylum. They survived the 'Great Dying' mass extinction, though their diversity was drastically reduced.
Field identification & locations
Identify by radial ribbing and bilateral symmetry across the surface of the shell valve. Commonly found in limestone road cuts, creek beds, and quarries globally.
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