gemstone

Moonstone

Orthoclase feldspar (KAlSi3O8) with albite lamellae

Hardness: 6-6.5 Mohs scale. Color: Colorless to white with blue or white adularescence (sheen). Luster: Vitreous to pearly. Crystal structure: Monoclinic. Cleavage: Perfect in two directions. Specific gravity: 2.56-2.59.

Hardness: 6-6
Color: Colorless to white with blue or white adularescence (sheen)
Luster: Vitreous to pearly

Identified July 19, 2026More gemstone →

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Physical properties

Formation & geological history

Formed in igneous and metamorphic rocks, specifically pegmatites. The characteristic 'glow' is caused by light scattering between alternating layers of orthoclase and albite feldspar (adularescence). Found in strata dating back to various geological periods from the Precambrian to Cenozoic.

Uses & applications

Primarily used in jewelry as cabochons or beads; also popular among crystal collectors for its aesthetic and perceived metaphysical properties.

Geological facts

Ancient Romans believed moonstone was formed from frozen moonlight. In 1970, Florida adopted moonstone as its official state gem to commemorate the Apollo 11 moon landing, despite moonstone not being naturally found in Florida.

Field identification & locations

Identified by its signature adularescence (a billowy light effect). In the field, look for feldspar cleavage and the shimmering schiller effect. Common locations include Sri Lanka, India, Myanmar, Madagascar, and Tanzania.

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