mineral
Tumbled smoky quartz
Quartz, silicon dioxide (SiO₂), brown variety colored by irradiation and trace aluminum
AI-generated identification · may be incorrectTypically Mohs hardness 7, translucent to transparent, brown to nearly black, with vitreous luster and no cleavage; this specimen is rounded and polished, showing conchoidal fractures and internal veils.
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Physical properties
Typically Mohs hardness 7, translucent to transparent, brown to nearly black, with vitreous luster and no cleavage; this specimen is rounded and polished, showing conchoidal fractures and internal veils.
Formation & geological history
Quartz crystallizes from silica-rich igneous and hydrothermal fluids, commonly in granite pegmatites and veins; its smoky color develops through natural radiation over geologic time, generally from Paleozoic to younger host rocks.
Uses & applications
Used as a decorative and lapidary stone, in jewelry, carvings, and mineral collections; common tumbled pieces have modest commercial value.
Geological facts
Smoky quartz is the brown variety of quartz; very dark material is sometimes called morion. Heating can remove or alter its color, while irradiation can artificially produce smoky tones.
Field identification & locations
Identify it by hardness, glassy luster, lack of cleavage, and resistance to scratching by steel; quartz will scratch glass. Common sources include Brazil, Switzerland, the United States, Madagascar, and Scotland.
