mineral
Smoky quartz crystal
Quartz, SiO₂ (smoky variety)
AI-generated identification · may be incorrectTranslucent brown-gray with a glassy luster and irregular, partly crystal-like faces. Mohs hardness 7; hexagonal crystal structure, no true cleavage, and conchoidal fracture. The image alone cannot confirm the identification.
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Physical properties
Translucent brown-gray with a glassy luster and irregular, partly crystal-like faces. Mohs hardness 7; hexagonal crystal structure, no true cleavage, and conchoidal fracture. The image alone cannot confirm the identification.
Formation & geological history
Forms when silica-rich fluids crystallize in cavities and fractures, commonly in granites and pegmatites. Smoky coloration typically results from natural irradiation acting on trace aluminum; crystals may range from geologically young to hundreds of millions of years old.
Uses & applications
Used in jewelry, carvings, and mineral collections; quartz is also important in glassmaking and electronics.
Geological facts
Quartz is one of Earth’s most abundant minerals. Smoky color can fade with prolonged exposure to strong heat or sunlight.
Field identification & locations
Look for glassy luster, hardness sufficient to scratch glass, and lack of cleavage; confirm with a hardness or refractive test. Common localities include Brazil, Switzerland, Madagascar, and the United States.
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