mineral

Polished smoky quartz

Quartz, silicon dioxide (SiO₂), smoky variety

AI-generated identification · may be incorrect

Hardness 7 Mohs; translucent brown to deep smoky-black color, vitreous luster, and trigonal crystal structure. Quartz has indistinct cleavage and conchoidal fracture; specific gravity is about 2.65.

Identified September 4, 2026More mineral →

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Physical properties

Hardness 7 Mohs; translucent brown to deep smoky-black color, vitreous luster, and trigonal crystal structure. Quartz has indistinct cleavage and conchoidal fracture; specific gravity is about 2.65.

Formation & geological history

Smoky quartz forms mainly in silica-rich hydrothermal veins, pegmatites, and cavities in igneous rocks; its color commonly results from natural radiation affecting aluminum impurities. The specimen is polished, so original crystal faces are obscured; age depends on its host rock, commonly Paleozoic to younger.

Uses & applications

Used as an ornamental stone, carving material, jewelry, and mineral-collection specimen; it has little industrial value in this polished form.

Geological facts

Its smoky color can fade with prolonged heating or strong sunlight. Very dark material may be morion, an opaque variety of smoky quartz.

Field identification & locations

Identify it by glassy luster, conchoidal fractures, translucency, and resistance to scratching by steel; it should not scratch glass easily if heavily coated, but quartz will. Common sources include Brazil, Switzerland, the United States, Madagascar, and Spain.