mineral

Moonstone

Orthoclase feldspar ((K,Na)AlSi3O8)

Hardness: 6-6.5 Mohs scale. Color: Peach, beige, or cream with white/blue adularescence. Luster: Vitreous to pearly. Crystal structure: Monoclinic. Specific gravity: 2.56-2.59.

Hardness: 6-6
Color: Peach, beige, or cream with white/blue adularescence
Luster: Vitreous to pearly

Identified May 6, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs scale. Color: Peach, beige, or cream with white/blue adularescence. Luster: Vitreous to pearly. Crystal structure: Monoclinic. Specific gravity: 2.56-2.59.

Formation & geological history

Formed from intergrowths of two types of feldspar (orthoclase and albite) that separate as the mineral cools. As light passes through these layers, it scatters to produce adularescence.

Uses & applications

Predominantly used in jewelry (cabochons and beads) and as a lapidary specimen for collectors. Believed by some to have metaphysical properties.

Geological facts

Ancient Romans believed moonstone was formed from frozen rays of moonlight. It is the Florida State Gemstone (commemorating the Moon landings), despite not being naturally found there.

Field identification & locations

Identify by its unique blue or white sheen (adularescence) that moves across the surface as the stone is rotated. Commonly found in Sri Lanka, India, and Madagascar.