mineraloid

Pearl

Aragonite / Calcium Carbonate (CaCO3)

Hardness: 2.5–4.5 (Mohs scale); Color: White, cream, pink, or silver; Luster: Pearly (iridescent nacrous); Crystal Structure: Orthorhombic microcrystalline; Specific Gravity: 2.60–2.85.

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

Identified April 21, 2026More mineraloid →

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Physical properties

Hardness: 2.5–4.5 (Mohs scale); Color: White, cream, pink, or silver; Luster: Pearly (iridescent nacrous); Crystal Structure: Orthorhombic microcrystalline; Specific Gravity: 2.60–2.85.

Formation & geological history

Biogenic formation; produced within the soft tissue (mantle) of a living shelled mollusk. Layers of nacre are deposited around a microscopic irritant over several years.

Uses & applications

Primarily used in jewelry (necklaces, earrings, rings), cosmetics (pearl powder), and as a traditional gemstone symbols.

Geological facts

Pearls are the only gemstones made by living creatures. The most famous pearl is 'La Peregrina,' which was owned by Mary I of England and Elizabeth Taylor.

Field identification & locations

Identify real pearls by the 'tooth test' (they feel gritty against teeth, while imitations feel smooth). Common locations include the Persian Gulf, waters around Japan, Australia, and French Polynesia.