mineral
Tumbled brown quartz (likely smoky quartz)
Quartz, silicon dioxide (SiO₂); brown coloration may be smoky quartz or iron-stained quartz
AI-generated identification · may be incorrectMohs hardness 7; translucent brown to gray-brown, vitreous to slightly waxy luster, conchoidal fracture, no cleavage, trigonal crystal structure. The piece appears naturally fractured or roughly tumbled and coated with surface dust or alteration residue.
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Physical properties
Mohs hardness 7; translucent brown to gray-brown, vitreous to slightly waxy luster, conchoidal fracture, no cleavage, trigonal crystal structure. The piece appears naturally fractured or roughly tumbled and coated with surface dust or alteration residue.
Formation & geological history
Quartz crystallizes from silica-rich hydrothermal fluids, pegmatites, and igneous veins; smoky coloration commonly results from irradiation-related defects with trace aluminum. Its exact geological age and locality cannot be determined from the image.
Uses & applications
Used for ornamental carving, lapidary work, jewelry, and mineral collecting; quartz is also important industrially in glass, electronics, abrasives, and engineered stone.
Geological facts
Quartz is one of Earth’s most abundant minerals and is the reference mineral for hardness 7 on the Mohs scale.
Field identification & locations
Check for glassy luster, conchoidal fracture, lack of cleavage, and resistance to scratching by a steel blade; a streak test should be white. Common sources include Brazil, Madagascar, the United States, and the Alps.
