gemstone

Pearls

Nacre, composed mainly of aragonite (CaCO₃) and conchiolin

AI-generated identification · may be incorrect

Pearls are typically white to cream with a pearly luster and rounded or irregular shapes. Nacre has Mohs hardness about 2.5–4.5; its microscopic aragonite layers are orthorhombic. The image appears to show loose, irregular pearls, possibly cultured.

Identified October 5, 2026More gemstone →

Explore Pearls in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed inside mollusks as layers of nacre around an irritant or implanted nucleus; modern cultured pearls are produced in farms. They form over months to years, rather than through geological rock-forming processes.

Uses & applications

Used in jewelry and decorative objects; crushed nacre has limited use in cosmetics and crafts.

Geological facts

Pearls are biogenic gem materials, not rocks, and are among the few gems produced by living organisms.

Field identification & locations

Look for nacreous luster, natural irregularities, and layered structure; common sources include China, Japan, Australia, and the Persian Gulf. A photo alone cannot establish whether these are natural, cultured, or imitation pearls.