mineral

Moonstone

Orthoclase Feldspar (containing Albite lamellae), (KAlSi3O8)

Hardness: 6.0-6.5 on Mohs scale; Color: Colorless to white with a blue or white adularescent sheen; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect in two directions; Specific Gravity: 2.56-2.59.

Hardness: 6
Color: Colorless to white with a blue or white adularescent sheen
Luster: Vitreous to pearly

Identified March 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous or metamorphic environments through the cooling of magma or the metamorphism of rocks. Its unique shimmer (adularescence) is caused by the alternating layers of orthoclase and albite that scatter light.

Uses & applications

Primarily used in jewelry (cabochons, rings, and pendants), as a birthstone for June, and highly valued by mineral collectors for its optical effects.

Geological facts

Ancient Romans believed moonstones were formed from frozen rays of moonlight. It is the state gem of Florida to commemorate the moon landing, despite not being found there naturally.

Field identification & locations

Identify in the field by its distinct 'shimmer' that appears to move across the surface as the stone is tilted. Found commonly in Sri Lanka, India, Madagascar, and Myanmar. Use a hardness test to distinguish it from plastic or glass imitations.

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

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

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

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