gemstone

Pearl necklace

Pearl (biogenic calcium carbonate, chiefly aragonite; CaCO₃)

AI-generated identification · may be incorrect

Hardness 2.5–4.5 Mohs; creamy white, nacreous luster, concentric micro-lamellar structure, and no cleavage. The uniform small beads and drilled holes indicate cultured pearls, likely freshwater or Akoya-style, rather than a natural geological rock.

Identified August 12, 2026More gemstone →

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Physical properties

Formation & geological history

Pearls form when nacre is deposited around an implanted bead or tissue irritant inside a mollusk; cultured examples typically develop over months to several years in freshwater mussels or marine oysters. They are biologically formed rather than products of rock crystallization.

Uses & applications

Used primarily in jewelry and ornaments. Value depends on pearl type, nacre quality, luster, surface cleanliness, shape, size, matching, and provenance.

Geological facts

Pearls are organic gemstones and can be damaged by acids, cosmetics, abrasion, and prolonged dryness. Nacre consists mainly of aragonite platelets bound by conchiolin.

Field identification & locations

Identify by soft nacreous luster, slight surface irregularities, cool feel, and a gritty response in a very cautious test against teeth; avoid destructive tests. Common sources include China, Japan, Australia, Indonesia, and the Philippines.