mineral

Tumbled smoky quartz (probable)

Quartz, silicon dioxide (SiO₂), likely smoky variety

AI-generated identification · may be incorrect

Translucent gray-brown to smoky gray, vitreous luster, hardness 7 Mohs, no true cleavage, conchoidal fracture, and trigonal crystal structure. The rounded shape indicates tumbling or natural abrasion; inclusions and surface glare limit certainty.

Identified August 25, 2026More mineral →

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Physical properties

Formation & geological history

Smoky quartz forms in silica-rich hydrothermal veins, pegmatites, and cavities of granitic rocks, commonly colored by natural irradiation affecting aluminum impurities. Specimens range from Precambrian to recent geological settings.

Uses & applications

Used as an ornamental and lapidary stone, in carvings, cabochons, and mineral collections; quartz also has major industrial uses in glass, electronics, and abrasives.

Geological facts

Quartz is one of Earth’s most abundant minerals and is piezoelectric. The specimen could alternatively be gray chalcedony or another quartz-rich material without tests.

Field identification & locations

Check for glassy luster, conchoidal fracture, lack of cleavage, and hardness sufficient to scratch ordinary glass; a streak test is white. Common sources include Brazil, Madagascar, Switzerland, and the United States.