mineral

Moonstone

Orthoclase (KAlSi3O8), specifically the variety showing adularescence

AI-generated identification · may be incorrect

Hardness: 6.0 – 6.5 (Mohs), Color: Colorless to white with a blue or white sheen, Luster: Vitreous to pearly, Crystal structure: Monoclinic, Cleavage: Perfect in two directions, Specific gravity: 2.56 – 2.59

Hardness: 6

Identified March 25, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous and metamorphic rocks, specifically within pegmatites. It consists of alternating layers of orthoclase and albite; when light falls between these layers, it scatters, causing the optical effect known as adularescence.

Uses & applications

Predominantly used as a gemstone in jewelry (rings, pendants, earrings), crystal healing practices, and as a popular specimen for mineral collectors.

Geological facts

In Roman mythology, it was believed moonstone was formed from frozen beams of moonlight. It is the Florida State Gemstone (commemorating the Apollo moon landings) and is a traditional birthstone for June.

Field identification & locations

Identify by its 'adularescence'—a milky bluish glow that moves across the surface as the stone is turned. It is commonly found in Sri Lanka, India, Myanmar, and Madagascar. Collectors look for high clarity and a strong blue 'flash'.