gemstone

Pearl necklace

Pearl—biogenic calcium carbonate, primarily aragonite (CaCO₃)

AI-generated identification · may be incorrect

Small, round white beads with pearly luster; Mohs hardness about 2.5–4.5, orthorhombic aragonite crystal structure, poor cleavage, and specific gravity about 2.60–2.85. The image cannot establish whether they are natural, cultured, or imitation pearls.

Identified August 31, 2026More gemstone →

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Physical properties

Formation & geological history

Pearls form when calcium-carbonate nacre is deposited in mollusks around an irritant; cultured pearls are farm-grown, commonly over months to several years, while natural pearls form rarely in wild mollusks. They are modern biogenic materials rather than rocks formed by standard igneous, sedimentary, or metamorphic processes.

Uses & applications

Used primarily in jewelry and ornament; high-quality natural and cultured pearls have significant gem value.

Geological facts

Nacre consists of microscopic aragonite platelets bonded by conchiolin, producing iridescent reflection. The clasp and uniform bead size suggest a manufactured jewelry strand.

Field identification & locations

Pearls feel cool, show layered nacre under magnification, and have slightly gritty surfaces when gently rubbed tooth-to-tooth; avoid this test because it can damage them. Common cultured sources include Japan, China, French Polynesia, Australia, and the Gulf region.