Pearl

Physical Properties

Hardness: 2.5–4.5; Color: White, cream, pink, silver; Luster: Pearly (iridescent); Crystal structure: Orthorhombic (Aragonite microcrystals); Cleavage: None; Specific Gravity: 2.60–2.85

Formation & Geological History

Biogenic origin; formed within the soft tissue (mantle) of living shelled mollusks through the deposition of layers of nacre around an irritant.

Uses & Applications

Primarily used in jewelry (necklaces, earrings, bracelets) and as decorative elements in fashion; historically used in cosmetics and traditional medicine.

Geological Facts

The 'Pearl of Lao Tzu' is one of the largest pearls ever found. Pearls are the only gemstones created by living creatures and do not require cutting or polishing to reveal their natural beauty.

Field Identification & Locations

Identified by their characteristic luster and 'tooth test' (feeling gritty against teeth). Found in both saltwater (oysters) and freshwater (mussels) environments globally, especially in Asia and the South Pacific.

Identified on: 5/19/2026

Mode: Standard