mineral
Tumbled amethyst
Quartz, crystalline silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation
AI-generated identification · may be incorrectMohs hardness 7; translucent violet to purple, vitreous luster, conchoidal fracture, trigonal crystal structure, no cleavage, specific gravity about 2.65. The rounded, glossy surface indicates tumbling and polishing.
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Physical properties
Mohs hardness 7; translucent violet to purple, vitreous luster, conchoidal fracture, trigonal crystal structure, no cleavage, specific gravity about 2.65. The rounded, glossy surface indicates tumbling and polishing.
Formation & geological history
Forms when silica-rich hydrothermal fluids fill cavities in volcanic rocks, especially basalt, where quartz crystals grow over long periods; deposits range from Paleozoic to Cenozoic in age. The image shows a polished specimen with visible inclusions and fractures.
Uses & applications
Used for jewelry, carvings, ornaments, mineral collections, and metaphysical products; high-quality transparent amethyst is faceted as a gemstone.
Geological facts
Amethyst is quartz colored purple by trace iron-related defects; heating commonly turns it yellow-orange, producing citrine-like material. Its color can fade with prolonged intense sunlight.
Field identification & locations
Identify by purple coloration, glassy luster, hardness, and lack of cleavage; common sources include Brazil, Uruguay, Zambia, and Mexico. This small, heavily included tumbled piece is likely commercial-grade.
