mineral
Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite
Hardness: 2.5–4.5 on Mohs scale; Color: White with iridescent orient; Luster: Pearly; Crystal structure: Orthorhombic (microcrystalline); Specific Gravity: 2.6 - 2.85
- Hardness
- 2
- Color
- White with iridescent orient
- Luster
- Pearly
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Physical properties
Hardness: 2.5–4.5 on Mohs scale; Color: White with iridescent orient; Luster: Pearly; Crystal structure: Orthorhombic (microcrystalline); Specific Gravity: 2.6 - 2.85
Formation & geological history
Organic formation by mollusks (oysters or mussels) depositing layers of nacre around an irritant; most modern pearls are cultured.
Uses & applications
Primarily used in jewelry, fashion accessories, and historical cosmetics or traditional medicine.
Geological facts
Pearls are the only gemstones made by living creatures. The iridescent luster is caused by the interference of light as it reflects off layers of nacre.
Field identification & locations
Identify by the 'tooth test' (feels gritty against teeth) and the presence of unique surface ridges visible under magnification. Commonly found in saltwater and freshwater mollusk farms in China, Japan, and the South Pacific.
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