mineral
Spiny Oyster Shell
Spondylus (Calcium Carbonate, CaCO3)
AI-generated identification · may be incorrectHardness: 3.5-4.0 (Mohs scale), Color: Orange, red, purple, white; Luster: Pearly to Vitreous; Crystal Structure: Trigonal (as Calcite) or Orthorhombic (as Aragonite); Specific Gravity: 2.7-2.9
- Hardness
- 3
- Color
- Orange, red, purple, white
- Luster
- Pearly to Vitreous
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Physical properties
Hardness: 3.5-4.0 (Mohs scale), Color: Orange, red, purple, white; Luster: Pearly to Vitreous; Crystal Structure: Trigonal (as Calcite) or Orthorhombic (as Aragonite); Specific Gravity: 2.7-2.9
Formation & geological history
Biogenic formation through marine mollusk shell growth in tropical waters. While not a mineral in the geological sense, it is treated as a biogenic gemstone used alongside minerals in jewelry.
Uses & applications
Used primarily in jewelry, lapidary arts, and Southwestern/Native American beadwork and inlay.
Geological facts
Spiny Oyster is not an oyster but a 'thorny oyster' or Spondylus, more closely related to scallops. It has been used as a form of currency and high-status jewelry for over 2,000 years in Andean and Mesoamerican cultures.
Field identification & locations
Identify by its vibrant tiered color bands and shell-like texture. In its raw form, it is covered in long spines. Commonly found in the Sea of Cortez off Baja California and the Gulf of Mexico.
