mineral

Smoky quartz (likely)

Quartz, silicon dioxide (SiO₂), naturally irradiated variety

AI-generated identification · may be incorrect

Dark smoky-brown to nearly black, translucent in thinner edges, with vitreous luster and conchoidal fracture; Mohs hardness 7, no cleavage, trigonal crystal structure. The rough form may show crystal faces or fracture surfaces.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Forms in silica-rich hydrothermal veins, pegmatites, and cavities in igneous rocks when trace aluminum is irradiated naturally, typically during late stages of granite formation. Individual crystals can range from geologically young to hundreds of millions of years old.

Uses & applications

Used as a collector mineral, ornamental stone, and occasionally in jewelry; darker transparent material is most desirable. Common rough pieces have modest commercial value.

Geological facts

Smoky quartz can be artificially irradiated or heat-treated, though natural color is common. Very dark material is sometimes called morion.

Field identification & locations

Common localities include Brazil, Switzerland, Scotland, Colorado, Arkansas, and Madagascar. Confirm with a glass-scratch test only cautiously: quartz should scratch ordinary glass, while its lack of cleavage distinguishes it from many dark minerals.