Rock Identifier
Pearls (likely freshwater cultured pearls) (Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin) — gemstone
gemstone

Pearls (likely freshwater cultured pearls)

Pearl: nacre, primarily aragonite (CaCO₃) with conchiolin

AI-generated identification · may be incorrect

Organic gemstones with pearly luster, white to cream coloration, and rounded/baroque forms. Mohs hardness is about 2.5–4.5; nacre consists of microscopic aragonite platelets in an organic matrix and has no cleavage.

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Physical properties

Organic gemstones with pearly luster, white to cream coloration, and rounded/baroque forms. Mohs hardness is about 2.5–4.5; nacre consists of microscopic aragonite platelets in an organic matrix and has no cleavage.

Formation & geological history

Pearls form when mollusks deposit concentric nacre layers around an irritant; cultured examples are nucleated and grown in freshwater mussels. The jewelry also contains human-made metal and likely synthetic stones, but the pearl beads are geological/biogenic materials.

Uses & applications

Used primarily in jewelry and ornamental objects. Freshwater cultured pearls commonly retail for roughly $10–$200 per strand, while higher-quality matched or designer pieces may cost more.

Geological facts

Pearl surfaces can show orient, ridges, pits, and irregular baroque shapes; these features distinguish many freshwater pearls from perfectly uniform glass or plastic imitations.

Field identification & locations

Common sources include China and the United States, especially the Mississippi basin. Identify by cool touch, subtle surface irregularities, nacreous luster, and a slightly gritty feel in a careful tooth test; avoid scratching or chemical tests.