mineral

Moonstone

Potassium Aluminum Silicate (KAlSi3O8) with inclusions of Albite

AI-generated identification · may be incorrect

Hardness: 6-6.5 (Mohs), Color: Clear to white with pearly or blue schiller (adularescence), Luster: Vitreous to pearly, Crystal structure: Monoclinic, Cleavage: Two directions at nearly 90 degrees

Hardness: 6-6

Identified July 12, 2026More mineral →

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Physical properties

Hardness: 6-6.5 (Mohs), Color: Clear to white with pearly or blue schiller (adularescence), Luster: Vitreous to pearly, Crystal structure: Monoclinic, Cleavage: Two directions at nearly 90 degrees

Formation & geological history

Formed in igneous and metamorphic rocks through the cooling of magma, where orthoclase and albite minerals separate into alternating layers, creating the light-scattering effect known as adularescence.

Uses & applications

Primarily used in jewelry for its optical effects; common in rings, pendants, and as tumbled stones for collectors and healing practitioners.

Geological facts

Legend says that moonstone is formed from frozen moonbeams. It is the birthstone for June and is prized for its 'adularescence' which is an optical phenomenon caused by light diffraction in internal mineral layers.

Field identification & locations

Identify in the field by its distinct iridescent 'glow' and hardness that can scratch glass. Often found in Sri Lanka, India, Myanmar, and Madagascar.