mineral
Polished smoky quartz
Quartz (SiO₂), smoky variety
AI-generated identification · may be incorrectMohs hardness 7; translucent to opaque smoky-brown with a vitreous luster and hexagonal crystal structure. Quartz has no cleavage and typically breaks with conchoidal fracture; this specimen is polished, so its natural crystal shape is not visible.
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Physical properties
Mohs hardness 7; translucent to opaque smoky-brown with a vitreous luster and hexagonal crystal structure. Quartz has no cleavage and typically breaks with conchoidal fracture; this specimen is polished, so its natural crystal shape is not visible.
Formation & geological history
Smoky quartz forms in silica-rich igneous and metamorphic settings, commonly in pegmatites and hydrothermal veins; its brown color results from natural irradiation affecting trace aluminum. The image does not establish the specimen’s age or exact source.
Uses & applications
Used for jewelry, carvings, and mineral collecting; quartz also has extensive industrial uses, though this polished piece is chiefly decorative.
Geological facts
Smoky quartz is a color variety of quartz, not a separate mineral species; its color can range from pale gray-brown to nearly black.
Field identification & locations
Look for brown translucence, glassy luster, hardness near 7, and lack of cleavage; common sources include Brazil, Madagascar, and the Alps. Polishing obscures diagnostic crystal faces.
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