gemstone

Pearl

Pearl; primarily aragonite (CaCO₃) in nacre

AI-generated identification · may be incorrect

Usually white to cream with a pearly, iridescent luster; Mohs hardness about 2.5–4.5, low durability, and no visible crystal faces because nacre forms concentric layers. The rounded bead appears likely cultured, though the image cannot confirm it.

Identified August 10, 2026More gemstone →

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Physical properties

Formation & geological history

A pearl forms when a mollusk deposits nacre around an irritant or implanted nucleus; cultured examples generally form over 6–24 months in oysters or freshwater mussels. Natural pearls are geologically recent and are not igneous, sedimentary, or metamorphic rocks.

Uses & applications

Used primarily in jewelry and ornamentation; value depends on luster, surface quality, shape, size, color, nacre thickness, and origin.

Geological facts

Most modern pearls are cultured rather than naturally formed. Saltwater pearls include Akoya, Tahitian, and South Sea varieties; freshwater pearls are commonly produced in China.

Field identification & locations

Identify by its soft nacreous glow, slightly irregular surface, and gritty feel against a tooth (avoid testing valuable pearls); imitation glass or plastic often looks uniformly glossy. Common sources include Japan, China, Australia, French Polynesia, and the Philippines.