mineral

Smoky quartz crystal

Quartz, silicon dioxide (SiO₂), smoky variety

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous luster, conchoidal fracture, and a trigonal crystal structure; this specimen is dark brown-gray, translucent, and partly embedded in a coarse matrix. The color results from irradiation-related defects, often enhanced naturally by surrounding radioactive minerals.

Identified September 4, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich hydrothermal fluids or late-stage cavities in igneous and metamorphic rocks; smoky coloration develops through natural irradiation over geological time, commonly from the Paleozoic to Precambrian depending on locality.

Uses & applications

Used as a collector specimen, ornamental stone, and occasionally in jewelry; quartz is also important industrially in glass, electronics, and abrasives.

Geological facts

The sharp planar faces and glassy dark body are characteristic of quartz, though the visible piece appears fractured rather than a complete crystal.

Field identification & locations

Common localities include Brazil, Switzerland, the United States, Madagascar, and Scotland; identify it by hardness, glassy luster, lack of cleavage, and conchoidal fracture. Matrix may include feldspar, mica, or iron oxides.