mineral
Brown tumbled stone, likely smoky quartz
Quartz (SiO₂), possibly iron-stained or smoky quartz
AI-generated identification · may be incorrectSmall, rounded, glossy brown specimen; quartz has Mohs hardness 7, vitreous luster, and a trigonal crystal structure, but the image does not show diagnostic crystal faces or cleavage. Identification from appearance alone is uncertain.
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Physical properties
Small, rounded, glossy brown specimen; quartz has Mohs hardness 7, vitreous luster, and a trigonal crystal structure, but the image does not show diagnostic crystal faces or cleavage. Identification from appearance alone is uncertain.
Formation & geological history
Quartz forms in many igneous, metamorphic, and hydrothermal settings over a wide range of geological ages; brown color can result from irradiation or iron staining. The smooth shape suggests it has been tumbled or polished.
Uses & applications
Used as a low-cost jewelry bead, decorative stone, or mineral-collection specimen.
Geological facts
Quartz is one of Earth’s most abundant minerals and has no true cleavage, breaking with a curved, conchoidal fracture.
Field identification & locations
Check for hardness near 7 and conchoidal fracture; glassy luster supports quartz, while a scratch test is best done inconspicuously. Quartz occurs worldwide, including Brazil, Madagascar, and the United States.
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Mineral