Pearl

Physical Properties

Hardness: 2.5-4.5 (Mohs); Color: White, cream, pink, silver; Luster: Pearly (iridescent); Crystal structure: Orthorhombic (Aragonite plates); Specific Gravity: 2.60-2.85

Formation & Geological History

Formed biogenically within the soft tissue (mantle) of a living shelled mollusk. Layers of nacre are deposited around a microscopic irritant over several years.

Uses & Applications

Predominantly used in jewelry (necklaces, rings, earrings), decorative arts, and sometimes in traditional cosmetics/medicine (pearl powder).

Geological Facts

They are the only gemstones in the world found inside living creatures. The most famous pearl is 'La Peregrina,' once owned by Elizabeth Taylor.

Field Identification & Locations

Identify by the 'tooth test' (feels gritty against teeth) or looking for surface growth concentricities. Found in both saltwater and freshwater environments worldwide.

Identified on: 4/21/2026

Mode: Standard