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 →

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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.

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Mineral

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Mineral/Rock

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