mineral
Likely smoky quartz crystal fragment
Quartz (SiO₂), probably smoky quartz
AI-generated identification · may be incorrectTranslucent brown-gray with a vitreous luster and irregular fracture; quartz has Mohs hardness 7, a trigonal crystal structure, and no cleavage. The image is insufficient to confirm the identification.
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Physical properties
Translucent brown-gray with a vitreous luster and irregular fracture; quartz has Mohs hardness 7, a trigonal crystal structure, and no cleavage. The image is insufficient to confirm the identification.
Formation & geological history
Quartz forms when silica-rich fluids crystallize in veins or cavities; smoky coloration commonly results from natural irradiation of trace aluminum in the crystal. Such deposits occur across many geological ages and settings.
Uses & applications
Quartz is used in jewelry, watches, electronics, and as a collector mineral; this small rough fragment is mainly suitable for collecting.
Geological facts
Smoky quartz’s color ranges from pale gray to deep brown and can fade with prolonged strong sunlight.
Field identification & locations
Check for glassy luster, hardness near 7, and lack of cleavage; a scratch test on an inconspicuous spot can help distinguish it from softer lookalikes. Common sources include Brazil, the Alps, and several regions of the United States.
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