mineral

Pearl (Biogenic Mineraloid)

Calcium carbonate (CaCO3) primarily as Aragonite

AI-generated identification · may be incorrect

Hardness: 2.5-4.5; Color: White, cream, pink, silver; Luster: Pearly (iridescent); Crystal structure: Orthorhombic (microcrystalline); Specific gravity: 2.60-2.85

Hardness: 2
Color: White, cream, pink, silver
Luster: Pearly (iridescent)

Identified June 28, 2026More mineral →

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Physical properties

Hardness: 2.5-4.5; Color: White, cream, pink, silver; Luster: Pearly (iridescent); Crystal structure: Orthorhombic (microcrystalline); Specific gravity: 2.60-2.85

Formation & geological history

Biogenic formation within the soft tissue (mantle) of a living shelled mollusk or other animal as a defense mechanism against irritants.

Uses & applications

Predominantly used in jewelry (necklaces, earrings, rings) and as a gemstone for collectors; historically used in cosmetics and traditional medicine.

Geological facts

Pearls are the only gemstones made by living creatures. The most famous pearl is 'La Peregrina', once owned by Elizabeth Taylor.

Field identification & locations

Identify by 'tooth test' (gritty feel against teeth) or looking for surface irregularities under magnification. Found in saltwater (oysters) or freshwater (mussels).