mineral

Moonstone

Orthoclase Feldspar (KAlSi3O8)

Hardness: 6.0-6.5 (Mohs scale), Color: Opalescent white to pale blue sheen (adularescence), Luster: Vitreous to pearly, Crystal structure: Monoclinic, Cleavage: Perfect in two directions, Specific gravity: 2.56-2.59

Hardness: 6

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling and slow separation of two types of feldspar (orthoclase and albite) within igneous or metamorphic rock. As the rock settles, thin layers of minerals create light interference, resulting in its signature glow.

Uses & applications

Primarily used as a gemstone in jewelry, decorative carvings, and as a popular specimen for crystal collecting and metaphysical purposes.

Geological facts

The characteristic blue glow of moonstone is known as 'adularescence.' It was highly popular during the Art Nouveau period and is the Floridian state gemstone, designated to commemorate the Moon landings.

Field identification & locations

Identify in the field by its distinct iridescent blue or milky white schiller when rotated under a light source. Commonly found in Sri Lanka, Myanmar, India, and Madagascar.