mineral
Tumbled amethyst
Amethyst, purple quartz (SiO₂)
AI-generated identification · may be incorrectPurple, translucent to opaque, with vitreous luster; Mohs hardness 7, trigonal crystal structure, and no true cleavage. The larger piece is rounded and polished; the smaller fragment appears to be a rough or broken purple crystal.
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Physical properties
Purple, translucent to opaque, with vitreous luster; Mohs hardness 7, trigonal crystal structure, and no true cleavage. The larger piece is rounded and polished; the smaller fragment appears to be a rough or broken purple crystal.
Formation & geological history
Amethyst forms when trace iron colors quartz in silica-rich fluids, commonly in volcanic-rock cavities. Deposits occur in geologically varied settings, often millions to hundreds of millions of years old; the photo cannot determine its specific age or source.
Uses & applications
Used for jewelry, beads, carvings, ornamental objects, and mineral collecting; quartz also has industrial and electronic uses.
Geological facts
Amethyst is the purple variety of quartz, and its color can fade with prolonged heat or strong sunlight.
Field identification & locations
Identify it by its purple color, glassy luster, hardness, and quartz-like fracture; common sources include Brazil, Uruguay, Zambia, and Madagascar. Polished small pieces commonly sell for about $2–$15 each, depending on color, size, and quality.
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