mineral

Pearl

Calcium Carbonate (CaCO3) with Conchiolin

Hardness: 2.5-4.5 (Mohs), Color: White, cream, pink, silver, or black, Luster: Pearly (orient), Structure: Amorphous/Orthorhombic (Aragonite)

Hardness: 2

Identified March 13, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Hardness: 2.5-4.5 (Mohs), Color: White, cream, pink, silver, or black, Luster: Pearly (orient), Structure: Amorphous/Orthorhombic (Aragonite)

Formation & geological history

Produced within the soft tissue (mantle) of living shelled mollusks; formed via concentric layers of nacre around an irritant.

Uses & applications

Primarily used in jewelry (necklaces, earrings, rings) and as a decorative organic gemstone; historically used in cosmetics.

Geological facts

Unlike other gemstones, pearls are organic and require no cutting or polishing to reveal their natural beauty. They are the birthstone for June.

Field identification & locations

Identified by their unique 'orient' (iridescence) and the 'tooth test' (gritty texture on teeth). Found in freshwater rivers and saltwater oceans globally.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral