mineral

Moonstone with Black Tourmaline

Feldspar (Orthoclase/Adularia) with Schorl inclusions, KAlSi3O8

Hardness: 6.0-6.5 Mohs. Color: White/creamy with blue adularescence and black inclusions. Luster: Vitreous to pearly. Crystal structure: Monoclinic. Cleavage: Perfect. Specific Gravity: 2.56-2.59.

Hardness: 6
Color: White/creamy with blue adularescence and black inclusions
Luster: Vitreous to pearly

Identified June 8, 2026More mineral →

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Physical properties

Hardness: 6.0-6.5 Mohs. Color: White/creamy with blue adularescence and black inclusions. Luster: Vitreous to pearly. Crystal structure: Monoclinic. Cleavage: Perfect. Specific Gravity: 2.56-2.59.

Formation & geological history

Formed in granitic and syenitic pegmatites. The blue sheen (adularescence) is caused by the intergrowth of orthoclase and albite, which scatters light. The black inclusions are commonly Schorl Tourmaline.

Uses & applications

Primarily used in jewelry for cabochons and beads, as well as by collectors for its unique optical properties and metaphysical associations.

Geological facts

Ancient Romans and Greeks theorized that moonstones were formed from frozen droplets of moonlight. The phenomenon of its glow is scientifically known as adularescence.

Field identification & locations

Identify by rotating under light to see a blue shimmer. Common locations include Sri Lanka, India, Myanmar, and Madagascar. Presence of black tourmaline is a classic feature of specimens from India.

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