mineral

Moonstone (Tumbled)

Orthoclase Feldspar (KAlSi3O8) with inclusions of Albite

Hardness: 6.0-6.5 on Mohs scale; Color: Colorless to white/grey with adularescence; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect in two directions; Specific gravity: 2.56-2.59

Hardness: 6
Color: Colorless to white/grey with adularescence
Luster: Vitreous to pearly

Identified March 23, 2026More mineral →

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Physical properties

Formation & geological history

Formed in plutonic and metamorphic rocks; its characteristic sheen (adularescence) occurs because of the intergrowth of two types of feldspar with different refractive indices that separate as the mineral cools.

Uses & applications

Primarily used in jewelry for cabochons and beads, and highly valued by mineral collectors and practitioners of crystal healing.

Geological facts

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

Field identification & locations

Identify by its 'adularescence' — a milky blue or white glow that moves across the stone when rotated. Commonly found in Sri Lanka, India, Myanmar, and Madagascar. Tumbled stones like this are usually identified by their translucency and internal shimmer.

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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)]

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Epidote

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

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