mineral

Moonstone

Potassium aluminum silicate (KAlSi3O8) with Albite (NaAlSi3O8)

Hardness: 6.0-6.5 on Mohs scale; Color: Colorless to white, peach, or blue; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect; Specific gravity: 2.56-2.59; Optical effect: Adularescence (bluish sheen)

Hardness: 6
Color: Colorless to white, peach, or blue
Luster: Vitreous to pearly

Identified June 9, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous or metamorphic environments when potassium-rich orthoclase and sodium-rich albite separate into thin intergrown layers during cooling, causing light to scatter internally.

Uses & applications

Primarily used in jewelry for cabochons, beads, and rings; also popular as a healing stone in metaphysical communities and for private mineral collections.

Geological facts

Ancient Romans and Greeks believed moonstone was created from frozen rays of moonlight. It is one of the official birthstones for the month of June and is the state gemstone for Florida (to honor the Apollo moon landings).

Field identification & locations

Identify in the field by its distinct adularescence (a glow that moves across the surface) and two directions of cleavage at nearly 90 degrees. Commonly found in Sri Lanka, India, Myanmar, and Madagascar.

Other mineral specimens

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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

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic