mineral
Tumbled quartz (likely clear quartz)
Quartz, silicon dioxide (SiO₂)
AI-generated identification · may be incorrectHardness 7 Mohs; transparent to translucent, colorless to faintly smoky, with a vitreous luster. It has a trigonal crystal structure and lacks cleavage, though tumbling produces a smooth rounded surface; internal fractures create bright reflections.
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Physical properties
Hardness 7 Mohs; transparent to translucent, colorless to faintly smoky, with a vitreous luster. It has a trigonal crystal structure and lacks cleavage, though tumbling produces a smooth rounded surface; internal fractures create bright reflections.
Formation & geological history
Quartz crystallizes from silica-rich hydrothermal fluids, pegmatites, and igneous rocks, and may later accumulate in sedimentary deposits. The specimen is human-tumbled and polished; its geological age cannot be determined from the image.
Uses & applications
Common in lapidary work, décor, crystal collections, abrasives, glassmaking, and electronics; clear gem-quality quartz is used occasionally in jewelry.
Geological facts
Its apparent rounded form and surface reflections indicate processing rather than natural crystal faces. It may be confused with glass, but quartz is harder and commonly shows irregular internal fractures or inclusions.
Field identification & locations
Likely quartz if it resists scratching by ordinary steel and shows no bubbles or perfectly uniform glassy texture; common worldwide, especially Brazil, Madagascar, and the United States. A definitive identification requires hardness, specific gravity, or refractive-index testing.
