mineral
Amethyst (rough crystal cluster)
Quartz, SiO₂; purple coloration commonly caused by trace iron and natural irradiation
AI-generated identification · may be incorrectMohs hardness 7; purple, translucent-to-transparent crystal tips over a pale, opaque matrix. Vitreous luster, trigonal crystal system, and no true cleavage; uneven to conchoidal fracture. The matrix may be another mineral or host rock and cannot be identified confidently from the image.
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Physical properties
Mohs hardness 7; purple, translucent-to-transparent crystal tips over a pale, opaque matrix. Vitreous luster, trigonal crystal system, and no true cleavage; uneven to conchoidal fracture. The matrix may be another mineral or host rock and cannot be identified confidently from the image.
Formation & geological history
Amethyst forms when silica-rich fluids deposit quartz in cavities and fractures, with trace iron and irradiation producing purple color. Such deposits occur in rocks of varied ages, including volcanic geodes and hydrothermal veins.
Uses & applications
Used in jewelry, carvings, and mineral collections; lower-grade material may be used for ornaments or decorative stone.
Geological facts
Amethyst is the purple variety of quartz, and its color can fade with prolonged exposure to strong sunlight or heat.
Field identification & locations
Look for purple quartz crystals with pointed hexagonal terminations and a glassy luster; common sources include Brazil, Uruguay, Zambia, and other quartz-bearing regions. The specimen appears to be a small rough cluster, but its locality and matrix are uncertain from the photo.
