mineral

Moonstone

Orthoclase (KAlSi3O8) with inclusions of Albite (NaAlSi3O8)

Hardness: 6-6.5 on Mohs scale; Color: Colorless to white, tan, or gray; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect in two directions; Adularescence: Blue or white glow.

Hardness: 6-6
Color: Colorless to white, tan, or gray
Luster: Vitreous to pearly

Identified May 5, 2026More mineral →

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Physical properties

Formation & geological history

Formed from molten rock deep in the earth; as it cools, the intermixed minerals (orthoclase and albite) separate into alternating layers, causing light to scatter. Commonly found in pegmatites and alpine veins.

Uses & applications

Used primarily as a gemstone in jewelry, decorative ornaments, and by crystal collectors for its aesthetic and metaphysical associations.

Geological facts

Ancient Romans believed moonstone was formed from frozen rays of the moon. It is the state gem of Florida to commemorate the moon landing, even though it is not found there.

Field identification & locations

Identify by its unique schiller effect (adularescence) that moves as the stone is tilted. Look for thin, alternating mineral layers. Commonly found in Sri Lanka, India, and Myanmar.

Other mineral specimens

See all

Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

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