mineral
Likely rough amethyst (purple quartz)
Quartz, SiO₂; amethyst variety
AI-generated identification · may be incorrectPurple, translucent to transparent with a vitreous luster; hexagonal crystal system, Mohs hardness 7, no cleavage, and conchoidal fracture. The small rough piece is consistent with amethyst, though color alone cannot confirm it.
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Physical properties
Purple, translucent to transparent with a vitreous luster; hexagonal crystal system, Mohs hardness 7, no cleavage, and conchoidal fracture. The small rough piece is consistent with amethyst, though color alone cannot confirm it.
Formation & geological history
Amethyst forms when iron-bearing quartz crystallizes in cavities and veins, commonly in volcanic rocks; deposits range from ancient to geologically recent.
Uses & applications
Used for jewelry, ornament, and mineral collections; larger, well-colored pieces are more valuable.
Geological facts
Amethyst’s purple color is associated with trace iron and natural irradiation.
Field identification & locations
Look for glassy luster, hardness sufficient to scratch glass, and typically hexagonal crystal faces; common sources include Brazil, Uruguay, and Zambia. Similar purple minerals or glass may require testing to distinguish.
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