gemstone

Pearl

Pearl; primarily aragonite (CaCO₃) with conchiolin

AI-generated identification · may be incorrect

Small, rounded cream-white bead with nacreous luster and likely surface drilled or polished. Mohs hardness is about 2.5–4.5; aragonite has orthorhombic crystal structure, with no visible cleavage and specific gravity around 2.60–2.85.

Identified August 22, 2026More gemstone →

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Physical properties

Formation & geological history

A cultured or natural pearl formed inside a mollusk when nacre layers of aragonite and organic conchiolin accumulate around an irritant or implanted nucleus. Formation typically takes months to several years in marine or freshwater environments; exact age is indeterminate.

Uses & applications

Used primarily in jewelry, ornamentation, and collectibles; pearl nacre is also used decoratively. This specimen appears small and ordinary rather than gem-grade.

Geological facts

Pearls are biogenic gemstones, not rocks in the strict petrologic sense, but they are geological specimens. Their iridescence results from light interference among microscopic nacre layers.

Field identification & locations

Identify by its cool, organic feel, soft nacreous glow, layered surface, and susceptibility to scratching; a tooth test is unreliable and can damage it. Common sources include Japan, China, Australia, the Philippines, and the Persian Gulf.