mineral

Moonstone

Orthoclase (KAlSi3O8) with Albite inclusions

AI-generated identification · may be incorrect

Hardness: 6-6.5 Mohs. Color: White or grayish with a pearly or opalescent adularescence. Luster: Vitreous to pearly. Crystal structure: Monoclinic. Specific gravity: 2.56-2.59.

Hardness: 6-6
Color: White or grayish with a pearly or opalescent adularescence
Luster: Vitreous to pearly

Identified July 9, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs. Color: White or grayish with a pearly or opalescent adularescence. Luster: Vitreous to pearly. Crystal structure: Monoclinic. Specific gravity: 2.56-2.59.

Formation & geological history

Formed in igneous pegmatites and metamorphic rocks. The characteristic sheen (adularescence) is caused by the intergrowth of two types of feldspar (orthoclase and albite) that separate as the magma cools, creating thin layers that scatter light.

Uses & applications

Primarily used in jewelry as a gemstone, especially in rings, pendants, and earrings. It is also a popular collector's mineral and used in metaphysical practices.

Geological facts

The Roman historian Pliny the Elder wrote that moonstone's appearance changed with the phases of the moon. It was highly popular during the Art Nouveau period and is the Florida State Gemstone (commemorating the Apollo moon landings).

Field identification & locations

Identify by the billowy blue or white light (adularescence) that moves across the surface when rotated. Found commonly in Sri Lanka, India, Myanmar, and Madagascar. Look for the characteristic pearly sheen in feldspar-rich areas.