mineral

Moonstone

Orthoclase (KAlSi3O8) with Albite (NaAlSi3O8) inclusions

Hardness: 6.0-6.5 (Mohs scale); Color: Colorless, white, or pale blue with adularescence; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect; Specific gravity: 2.56-2.59

Hardness: 6
Color: Colorless, white, or pale blue with adularescence
Luster: Vitreous to pearly

Identified June 24, 2026More mineral →

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Physical properties

Hardness: 6.0-6.5 (Mohs scale); Color: Colorless, white, or pale blue with adularescence; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect; Specific gravity: 2.56-2.59

Formation & geological history

Formed from molten interior rock cooling at high temperatures, followed by unmixing of two feldspar minerals during cooling into thin alternating layers. Found in igneous and metamorphic environments.

Uses & applications

Primarily used in jewelry for its unique optical effect (adularescence) and as a birthstone for June. Also popular for metaphysical and ornamental collecting.

Geological facts

The shimmering blue light that appears to float across the surface is called adularescence, caused by light scattering between microscopic layers of orthoclase and albite. It is the state gemstone of Florida.

Field identification & locations

Identify by looking for a blue or white billowy light effect (schiller) when tilted. It is commonly found in Sri Lanka, India, Myanmar, and Madagascar. High-quality specimens have a blue sheen and are nearly transparent.

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Mineral/Rock

Banded Gneiss (River Rock/Pebble)

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Metamorphic Rock

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mineral