Pearl

Physical Properties

Hardness: 2.5-4.5 (Mohs); Color: White, cream, pink, silver, or black; Luster: Pearly (iridescent); Crystal structure: Orthorhombic; 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 created as a defense mechanism against irritants by secreting layers of nacre.

Uses & Applications

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

Geological Facts

The 'Pearl of Lao Tzu' is one of the largest pearls ever found, weighing over 6 kilograms. Pearls are the only gemstones created by living creatures.

Field Identification & Locations

Identify by the 'tooth test' (feels gritty when rubbed against teeth) and its characteristic orient (iridescence). Found in both saltwater and freshwater mollusks globally.

Identified on: 5/1/2026

Mode: Standard