mineral

Moonstone (Feldspar variety)

Orthoclase Feldspar (KAlSi3O8)

Hardness: 6.0-6.5 on Mohs scale. Color: Translucent to opaque with white, grey, or silvery-pink tones. Luster: Vitreous to pearly. Crystal Structure: Monoclinic. Exhibits adularescence (a internal glow or flash).

Hardness: 6
Luster: Vitreous to pearly

Identified March 24, 2026More mineral →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Formed from cooling magma in igneous intrusions like pegmatites. The distinct visual 'glow' is caused by intergrowth of two types of feldspar (orthoclase and albite) that separate as the mineral cools.

Uses & applications

Primary use is in jewelry as gemstones (typically cut as cabochons). Also used as a healing stone in metaphysical communities and as a collector's specimen.

Geological facts

Ancient Romans theorized that moonstones were formed from frozen moonlight. It is the Florida State Gemstone (commemorating the Apollo moon landings) even though it is not naturally found there.

Field identification & locations

Identify by its 'adularescence' (shifting light across the surface) and its moderate hardness. Found globally in Sri Lanka, India, Myanmar, Brazil, and parts of the USA. Collectors look for clarity and the strength of the light effect.

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