
mineral
Quartz (Smoky/Brown variety)
Silicon dioxide (SiO2)
AI-generated identification · may be incorrectHardness 7. Brown to greyish-brown color. Vitreous luster. Hexagonal crystal structure. No cleavage, conchoidal fracture.
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Physical properties
Hardness 7. Brown to greyish-brown color. Vitreous luster. Hexagonal crystal structure. No cleavage, conchoidal fracture.
Formation & geological history
Forms in igneous and metamorphic rocks, often in pegmatites. The color comes from natural irradiation of aluminum impurities.
Uses & applications
Used in jewelry, electronics, and as a collector's mineral.
Geological facts
Smoky quartz was historically used for sunglasses in China in the 12th century.
Field identification & locations
Identified by its hardness (scratches glass), conchoidal fracture, and brownish color. Common worldwide.