gemstone

Pearl

Nacre (aragonite, CaCO₃, in a conchiolin matrix)

AI-generated identification · may be incorrect

Hardness 2.5–4.5 Mohs; rounded, smooth, and typically white, cream, pink, or gray with pearly orient (iridescent luster). It has a layered, noncrystalline organic-mineral structure and no cleavage.

Identified August 22, 2026More gemstone →

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Physical properties

Hardness 2.5–4.5 Mohs; rounded, smooth, and typically white, cream, pink, or gray with pearly orient (iridescent luster). It has a layered, noncrystalline organic-mineral structure and no cleavage.

Formation & geological history

Formed inside mollusks when successive nacre layers surround an irritant; most modern examples are cultured. Growth commonly takes 6 months to several years, with no single geological age because formation is biological.

Uses & applications

Used primarily in jewelry, ornaments, buttons, and collectibles. Value depends on size, shape, surface quality, nacre thickness, color, and luster.

Geological facts

The image appears to show a spherical cultured pearl, possibly freshwater or saltwater; a blue reflection may be surface lighting rather than natural body color.

Field identification & locations

Identify by its cool feel, layered pearly luster, and fine granular feel when gently rubbed against a tooth; glass feels smooth. Common sources include Japan, China, French Polynesia, Australia, and Indonesia.