mineral

Smoky quartz crystal/rough fragment

Quartz (SiO₂), likely smoky quartz

AI-generated identification · may be incorrect

Typically Mohs hardness 7, vitreous luster, translucent gray-brown to smoky coloration, conchoidal fracture, and no cleavage; hexagonal crystal structure. The pictured piece appears irregular and partly crystalline, with possible surface weathering or matrix.

Identified August 11, 2026More mineral →

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Physical properties

Formation & geological history

Forms in silica-rich hydrothermal veins, cavities in igneous rocks, and pegmatites; smoky color commonly results from natural irradiation acting on aluminum impurities. Individual crystals may form over long spans of geologic time, from Precambrian to recent hydrothermal settings.

Uses & applications

Used for ornaments, carvings, crystal collecting, and occasionally jewelry; quartz is also important industrially in glass, electronics, abrasives, and engineered stone.

Geological facts

Smoky quartz is the brown variety of quartz; darker examples are sometimes called morion. Color can fade with prolonged heating or intense light.

Field identification & locations

Identify by hardness, glassy luster, lack of cleavage, and conchoidal fracture; it should scratch ordinary glass but not be scratched by a steel knife. Common sources include Brazil, Switzerland, Madagascar, the United States, and Scotland.