gemstone

Pearl

Calcium Carbonate (Aragonite/Calcite) with Conchiolin, CaCO3

Hardness: 2.5 to 4.5 on the Mohs scale, Color: White, cream, silver, gold, pink, purple, or black, Luster: Pearlescent or nacreous, Crystal Structure: Orthorhombic (microcrystalline aragonite platelets)

Hardness: 2

Identified July 31, 2026More gemstone →

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Physical properties

Formation & geological history

Formed within the soft tissue (mantle) of a living shelled mollusk, such as an oyster or mussel, as a defense mechanism against an irritant.

Uses & applications

Primarily used in fine jewelry such as necklaces, earrings, and rings.

Geological facts

Unlike most gemstones that are mined from the earth, pearls are organic gems produced entirely by living organisms.

Field identification & locations

Identified by its characteristic luster (orient) and organic irregularities. Natural and cultured pearls are found in oceans and freshwater lakes globally, heavily farmed in countries like China, Japan, and Australia.

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