gemstone

Cultured freshwater pearls

Pearl; primarily aragonite (CaCO₃) in nacre with an organic conchiolin matrix

AI-generated identification · may be incorrect

Cream to white, rounded but irregular beads with pearly luster; Mohs hardness about 2.5–4.5. Nacre is built from microscopic aragonite crystals; the photo shows a strung jewelry strand, and individual pearls cannot be confidently graded from the image.

Identified October 5, 2026More gemstone →

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Physical properties

Formation & geological history

Formed in freshwater mussels when nacre layers grow around an implanted nucleus or irritant; these are likely cultured, but age and origin cannot be determined visually.

Uses & applications

Used in necklaces and other jewelry; pearls are valued for luster, shape, size, surface quality, and matching.

Geological facts

Pearls are biogenic gemstones rather than rocks in the strict sense, but qualify as geological specimens under the requested definition.

Field identification & locations

Pearls are identified by nacreous luster and natural-looking surface texture; distinguish them from glass or plastic by expert inspection, since appearance alone is inconclusive. Freshwater pearls are cultured widely in China and elsewhere.