mineral

Moonstone (specifically White Moonstone/Adularia)

Potassium aluminum silicate ((K,Na)AlSi3O8)

Hardness: 6-6.5 (Mohs scale); Color: White, colorless, or pearly; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Specific gravity: 2.56-2.59; Optical effect: Adularescence (a milky bluish sheen).

Hardness: 6-6
Color: White, colorless, or pearly
Luster: Vitreous to pearly

Identified April 3, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous and metamorphic rocks under specific cooling conditions where two types of feldspar (orthoclase and albite) separate into thin, alternating layers, causing light to scatter.

Uses & applications

Primarily used in jewelry as cabochons, rings, and pendants; also used by collectors and in metaphysical healing practices.

Geological facts

Ancient Romans and Greeks associated moonstones with their lunar deities. The phenomenon of its shimmering light is called adularescence, named after Mt. Adular in Switzerland, a famous source.

Field identification & locations

Identify by its characteristic soft, pearly sheen that moves across the surface as the stone is turned (adularescence). It has two directions of cleavage at nearly 90 degrees. Commonly found in Sri Lanka, India, and Myanmar.

Other mineral specimens

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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)]

mineral

Epidote

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

mineral