gemstone

Moonstone

Orthoclase feldspar ((K,Na)AlSi3O8) with inclusions of Albite

Hardness: 6-6.5 (Mohs scale); Color: White, blue-white, or brownish; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect in two directions; Specific Gravity: 2.56-2.59; Adularescence.

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

Identified July 17, 2026More gemstone →

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Physical properties

Formation & geological history

Formed from intergrown layers of orthoclase and albite during the cooling of magma. As the mineral cools, the two feldspars separate into stacked layers, causing light to scatter (interference effect).

Uses & applications

Primarily used in jewelry as cabochons or beads, and highly valued by collectors of crystals and metaphysical items.

Geological facts

It is recognized as the Florida State Gemstone (to commemorate the Moon landing). Ancient Romans believed moonstones were formed from solidified rays of the moon.

Field identification & locations

Identify by its unique 'adularescence' (a billowy blue or white light that moves across the stone). Found commonly in Sri Lanka, India, Myanmar, and Madagascar. Collectors should look for clear stones with strong blue sheen.

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