gemstone

Pearl (Biogenic Gemstone)

Calcium Carbonate (Aragonite and Calcite) with Conchiolin

Hardness (Mohs scale): 2.5-4.5. Color: Typically white, cream, silver, gold, pink, black. Luster: Pearly. Crystal structure: Orthorhombic (Aragonite) and Trigonal (Calcite). Cleavage: None. Specific gravity: 2.6-2.8.

Color: Typically white, cream, silver, gold, pink, black
Luster: Pearly

Identified August 2, 2026More gemstone →

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Physical properties

Formation & geological history

Formed by mollusks (such as oysters and mussels) as a defense mechanism against irritants. Composed of concentric layers of nacre.

Uses & applications

Primarily used in jewelry, such as necklaces, earrings, and rings. Cultured pearls are widely produced for this purpose.

Geological facts

Pearls are one of the few gemstones formed by living organisms. Natural pearls are extremely rare, making cultured pearls the standard in modern jewelry.

Field identification & locations

Identified by their characteristic pearly luster and smooth surface. The 'tooth test' (rubbing a pearl gently against the teeth) can help distinguish real pearls (which feel slightly gritty) from imitations (which feel smooth).

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