gemstone

Moonstone

Orthoclase and Albite (KAlSi3O8 / NaAlSi3O8)

AI-generated identification · may be incorrect

Hardness: 6.0-6.5 (Mohs scale); Color: White, blue-white, or colorless; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect in two directions; Features adularescence (a milky blue sheen).

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

Identified July 19, 2026More gemstone →

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Physical properties

Formation & geological history

Formation through the intergrowth of two types of feldspar, orthoclase and albite, which separate into thin layers as the magma cools. As light falls between these layers, it scatters in many directions, producing the adularescence effect.

Uses & applications

Primarily used in jewelry as cabochons, beads, and faceted stones. It is highly valued by collectors for its optical properties.

Geological facts

Ancient Romans believed moonstone was formed from frozen beams of moonlight. It is the state gem of Florida to commemorate the Apollo moon landings.

Field identification & locations

Identified by its characteristic pearly 'schiller' or adularescence. Commonly found in Sri Lanka, India, Myanmar, and Madagascar. Collectors look for high transparency and a strong blue sheen in high-quality specimens.