mineral

Smoky quartz

Quartz, silicon dioxide (SiO₂), smoky variety

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent smoky brown to gray, with vitreous luster and irregular/conchoidal fracture. Hexagonal crystal structure; the specimen appears massive and partly crystalline, with no prominent cleavage and density near 2.65 g/cm³.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

Forms in silica-rich hydrothermal veins, pegmatites, and cavities in igneous rocks; smoky color typically results from natural irradiation of trace aluminum in quartz. Individual specimens may form over broad geologic intervals, commonly from Paleozoic to younger host rocks.

Uses & applications

Used as a durable ornamental and lapidary stone, in jewelry, carvings, and mineral collections; quartz is also important industrially in glass, electronics, and abrasives.

Geological facts

The smoky color can fade with strong heating or sunlight, and may be artificially induced by irradiation. Its dark transparent appearance distinguishes it from ordinary gray chalcedony, which lacks visible quartz crystal texture.

Field identification & locations

Identify by glassy luster, hardness sufficient to scratch ordinary glass, lack of cleavage, and smoky coloration; common localities include Brazil, Switzerland, the United States, Madagascar, and Scotland. This rough piece appears natural but cannot be confirmed from a photograph alone.