mineral

Pearl

Calcium Carbonate (CaCO3) with Conchiolin

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

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

Identified April 27, 2026More mineral →

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Physical properties

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

Formation & geological history

Biogenic formation within the soft tissue (mantle) of a living shelled mollusk or fossilized in ancient sedimentary deposits. Formed as a defense mechanism against irritants over several years.

Uses & applications

Primarily used in fine jewelry (necklaces, earrings, rings), cosmetics, and traditional medicines in some cultures.

Geological facts

Pearls are the only gemstones made by living creatures. The 'Hope Pearl' is one of the largest ever found, weighing 450 carats. Most pearls today are 'cultured', meaning human intervention started the process.

Field identification & locations

Identify by the 'tooth test' (rubbing against teeth feels gritty, whereas fakes feel smooth) and its unique luster. Natural pearls are found in both freshwater and saltwater environments.