sedimentary
Bivalve Fossil (Clam)
Class Bivalvia (Calcium Carbonate, CaCO3)
Hardness: 3 (Mohs scale); Color: White to off-white/gray; Luster: Dull to pearly; Structure: Bilateral symmetry between shells; Specific Gravity: 2.7-2.9
- Hardness
- 3 (Mohs scale)
- Color
- White to off-white/gray
- Luster
- Dull to pearly
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Physical properties
Hardness: 3 (Mohs scale); Color: White to off-white/gray; Luster: Dull to pearly; Structure: Bilateral symmetry between shells; Specific Gravity: 2.7-2.9
Formation & geological history
Formed through the process of permineralization or replacement in shallow marine environments. While bivalves appeared in the Cambrian, well-preserved calcified specimens like this often date from the Cenozoic to the present.
Uses & applications
Used primarily for educational purposes, scientific study of paleoenvironments, jewelry making (buttons/beads), and as decorative collector items.
Geological facts
Bivalves are one of the most successful animal groups in earth's history. Unlike most animals, they have no head and their body is compressed between two hinged shells. Some fossilized specimens can grow to over 4 feet in length (Giant Clams).
Field identification & locations
Identify by looking for concentric growth lines and radial ribs. Commonly found in sedimentary rock layers like limestone or shale near coastal regions or ancient inland sea beds.
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