mineral

Moonstone

Feldspar (Orthoclase with Albite), (K,Na)AlSi3O8

Hardness: 6-6.5 Mohs scale; Color: Colorless to white with blue or white schiller (adularescence); Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect at two planes; Specific gravity: 2.56-2.59

Hardness: 6-6
Luster: Vitreous to pearly

Identified May 17, 2026More mineral →

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Physical properties

Formation & geological history

Formed in plutonic igneous rocks (pegmatites) through the intergrowth of orthoclase and albite. As the cooling magma solidifies, the two minerals separate into thin, alternating layers, which causes the scattering of light known as adularescence.

Uses & applications

Primarily used in jewelry (cabochons, beads, rings) and as a collector's gemstone. Historically used in talismans and decorative arts.

Geological facts

The unique glow is called adularescence, named after Mt. Adular in Switzerland, a famous source. It is the state gem of Florida in honor of the moon landings, despite not being found there.

Field identification & locations

Identify by its characteristic blue or white 'shimmer' that moves across the surface when tilted. Commonly found in Sri Lanka, India, Myanmar, and Madagascar. Collectors look for high transparency and strong blue flashes.

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

mineral

Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral