mineral
Smoky quartz crystal
Quartz (SiO₂), likely smoky variety
AI-generated identification · may be incorrectTranslucent gray-brown with vitreous luster and irregular crystal faces; Mohs hardness 7, trigonal crystal system, no cleavage, conchoidal fracture. The photo alone cannot confirm the variety; similar-looking minerals are possible.
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Physical properties
Translucent gray-brown with vitreous luster and irregular crystal faces; Mohs hardness 7, trigonal crystal system, no cleavage, conchoidal fracture. The photo alone cannot confirm the variety; similar-looking minerals are possible.
Formation & geological history
Quartz commonly crystallizes from silica-rich fluids in cavities and pegmatites, over a wide range of geological ages. Smoky coloration usually results from irradiation acting on trace aluminum impurities.
Uses & applications
Used for jewelry, carving, and mineral collecting; quartz is also important in glassmaking and electronics.
Geological facts
Quartz is one of Earth’s most abundant minerals; smoky color can range from pale gray to nearly black.
Field identification & locations
Check for hardness near 7, glassy luster, and conchoidal fracture; common sources include Brazil, Madagascar, the Alps, and the United States. Avoid scratch-testing a valued specimen.
