mineral

Smoky quartz (small rough fragment)

Quartz, SiO₂; smoky variety

AI-generated identification · may be incorrect

Translucent gray-brown with a vitreous luster and irregular conchoidal fractures; quartz is trigonal, Mohs hardness 7, with no cleavage and specific gravity about 2.65. Identification is tentative from the image alone.

Identified October 4, 2026More mineral →

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Physical properties

Formation & geological history

Forms in silica-rich pegmatites, hydrothermal veins, and cavities in igneous or metamorphic rocks. Its smoky color commonly results from natural irradiation affecting trace aluminum in the crystal lattice; specimens may range from geologically recent to ancient.

Uses & applications

Used as a decorative and jewelry stone, and collected as a mineral specimen; quartz also has extensive industrial uses in glassmaking and electronics.

Geological facts

Smoky quartz can range from nearly colorless gray to very dark brown or black; heating or irradiation can alter its color.

Field identification & locations

Look for glassy luster, hardness sufficient to scratch ordinary glass, and conchoidal fracture rather than cleavage. Common sources include Brazil, the Alps, Madagascar, and the United States; the pictured fragment is too small and indistinct for a certain identification.