mineral
Tumbled smoky quartz
Quartz (SiO₂), brown smoky variety
AI-generated identification · may be incorrectMohs hardness 7; translucent smoky-brown color with vitreous-to-waxy luster and no visible cleavage. It has a trigonal crystal structure, but tumbling has rounded and polished the specimen.
Identified More mineral →
Explore Tumbled smoky quartz in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Mohs hardness 7; translucent smoky-brown color with vitreous-to-waxy luster and no visible cleavage. It has a trigonal crystal structure, but tumbling has rounded and polished the specimen.
Formation & geological history
Smoky quartz forms in silica-rich hydrothermal veins, pegmatites, and cavities, commonly acquiring color from irradiation affecting trace aluminum. It occurs in rocks ranging from Precambrian to recent age.
Uses & applications
Used as a decorative and lapidary stone, jewelry component, and collector specimen; this small tumbled piece has modest commercial value.
Geological facts
The smoky color can fade with prolonged heating or intense light, and natural smoky quartz is often distinguished from artificially irradiated quartz by locality and internal zoning.
Field identification & locations
Common sources include Brazil, Switzerland, Madagascar, the United States, and Scotland. Identify it by its glassy polish, gray-brown translucency, hardness, and lack of cleavage; the image alone cannot exclude dark agate or obsidian.
