mineral

Tumbled smoky quartz

Quartz, SiO₂; smoky variety colored by irradiation-induced defects

AI-generated identification · may be incorrect

Translucent brown-gray, vitreous luster, irregular fracture, no cleavage; Mohs hardness 7, trigonal crystal structure, specific gravity about 2.65. The image shows a small polished/tumbled piece, so its natural crystal form is obscured.

Identified September 29, 2026More mineral →

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Physical properties

Formation & geological history

Quartz crystallizes from silica-rich fluids, commonly in pegmatites and hydrothermal veins; smoky coloration develops through natural radiation acting on trace aluminum in the crystal. Quartz deposits span many geological ages.

Uses & applications

Used in jewelry, ornaments, and mineral collections; quartz is also an important industrial source of silica, though this small specimen is mainly decorative.

Geological facts

Smoky quartz’s color ranges from pale gray to nearly black and may fade with prolonged strong sunlight.

Field identification & locations

Look for glassy luster, hardness sufficient to scratch glass, and lack of cleavage; common sources include Brazil, the Alps, and the United States. Similar brown glass can be distinguished by quartz’s hardness and natural internal features.