Pearl

Physical Properties

Hardness: 2.5–4.5; Color: White, cream, silver, or pink; Luster: Pearly (nacreous); Crystal structure: Orthorhombic/Hexagonal; 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 formed by concentric layers of nacre around an irritant.

Uses & Applications

Primarily used in jewelry (necklaces, earrings, rings) and as a decorative gemstone.

Geological Facts

Pearls are the only gemstones created by living animals. Notable historical specimens include 'La Peregrina,' which was owned by Mary I of England and Elizabeth Taylor.

Field Identification & Locations

Identify by the 'tooth test' (feels gritty against teeth) or by observing nacre layers under magnification. Found in both freshwater and saltwater environments globally.

Identified on: 4/27/2026

Mode: Standard