gemstone

Pearl

Nacre (aragonite, CaCO₃, with conchiolin)

AI-generated identification · may be incorrect

Hardness about 2.5–4.5 Mohs; creamy white, pinkish, or gray with pearly luster and concentric nacre layers. It is an organic, noncrystalline composite rather than a conventional rock or crystal.

Identified August 26, 2026More gemstone →

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Physical properties

Hardness about 2.5–4.5 Mohs; creamy white, pinkish, or gray with pearly luster and concentric nacre layers. It is an organic, noncrystalline composite rather than a conventional rock or crystal.

Formation & geological history

Formed by mollusks—commonly oysters or freshwater mussels—depositing nacre around an irritant; natural pearls are geologically recent, while cultured pearls are human-initiated but naturally grown. The image appears to show a spherical pearl, though a shell bead or imitation cannot be ruled out visually.

Uses & applications

Used primarily in jewelry, ornament, and cultured-pearl production; powdered nacre has limited traditional and cosmetic uses.

Geological facts

Pearl color depends on mollusk species, nacre thickness, and trace elements; “orient” describes shifting iridescence caused by light interacting with nacre layers.

Field identification & locations

Identify by its cool feel, layered/iridescent surface, and slightly gritty tooth test—never use this on valuable pearls; glass or plastic imitations feel smooth and uniform. Common sources include Japan, China, Australia, the Philippines, and the Persian Gulf.