mineral

Moonstone (Tumbled)

Orthoclase (Potassium Feldspar) - (K,Na)AlSi3O8

AI-generated identification · may be incorrect

Hardness: 6-6.5 Mohs. Color: Creamy white with blueish adularescence. Luster: Vitreous to pearly. Crystal Structure: Monoclinic. Cleavage: Perfect in two directions. Specific Gravity: 2.56-2.59.

Hardness: 6-6
Color: Creamy white with blueish adularescence
Luster: Vitreous to pearly

Identified July 7, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs. Color: Creamy white with blueish adularescence. Luster: Vitreous to pearly. Crystal Structure: Monoclinic. Cleavage: Perfect in two directions. Specific Gravity: 2.56-2.59.

Formation & geological history

Formed in igneous and metamorphic rocks through the slow cooling of magma where orthoclase and albite separate into microscopic layers. These layers cause the characteristic scattering of light known as adularescence.

Uses & applications

Primarily used as a gemstone in jewelry, decorative ornaments, and highly valued by mineral collectors for its unique optical effects.

Geological facts

The 'glow' of moonstone is caused by light reflecting off alternating layers of two different feldspar minerals. In ancient Rome and India, it was believed to be created from frozen moonlight.

Field identification & locations

Identify by its 'adularescence' (a blueish sheen that moves across the surface). Commonly found in Sri Lanka, India, Myanmar, and Madagascar. Look for the characteristic light-play when tilted under a direct light source.