mineral
Pearl
Calcium carbonate (CaCO3) - Aragonite/Calcite variety
Hardness: 2.5–4.5; Color: White, cream, silver, or pink; Luster: Pearly (nacreous); Crystal structure: Orthorhombic/Hexagonal; Cleavage: None; Specific Gravity: 2.60–2.85
- Hardness
- 2
- Color
- White, cream, silver, or pink
- Luster
- Pearly (nacreous)
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Physical properties
Hardness: 2.5–4.5; Color: White, cream, silver, or pink; Luster: Pearly (nacreous); Crystal structure: Orthorhombic/Hexagonal; Cleavage: None; Specific Gravity: 2.60–2.85
Formation & geological history
Biogenic formation within the soft tissue (mantle) of a living shelled mollusk. It is formed by concentric layers of nacre around an irritant.
Uses & applications
Primarily used in jewelry (necklaces, earrings, rings) and as a decorative gemstone.
Geological facts
Pearls are the only gemstones created by living animals. Notable historical specimens include 'La Peregrina,' which was owned by Mary I of England and Elizabeth Taylor.
Field identification & locations
Identify by the 'tooth test' (feels gritty against teeth) or by observing nacre layers under magnification. Found in both freshwater and saltwater environments globally.
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