mineral

Moonstone

Orthoclase Feldspar ((K,Na)AlSi3O8)

Hardness: 6-6.5 (Mohs scale); Color: White, opalescent, or translucent; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Specific gravity: 2.56-2.59; Optical effect: Adularescence (bluish sheen)

Hardness: 6-6
Color: White, opalescent, or translucent
Luster: Vitreous to pearly

Identified March 29, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous or metamorphic environments when two types of feldspar (orthoclase and albite) intergrow and then separate into thin layers as the magma cools, creating light interference.

Uses & applications

Primarily used as a gemstone in jewelry (rings, pendants) and for decorative carvings. It is also a popular collector's mineral and used in holistic practices.

Geological facts

Ancient Romans believed moonstones were created from solidified drops of moonlight. It is the Florida State Gemstone, designated to commemorate the Moon landing, though it is not naturally found there.

Field identification & locations

Identify by its unique 'shiller' or adularescence effect when rotated under light. Commonly found in Sri Lanka, India, Myanmar, and Madagascar. Collectors look for high clarity and strong blue flash.