mineral
Amethyst druzy quartz
Quartz, SiO₂; purple variety colored mainly by iron-related defects
AI-generated identification · may be incorrectHardness 7 Mohs; vitreous luster; translucent purple-to-gray druzy crystals on a darker matrix, with conchoidal fracture and no cleavage. Specific gravity is about 2.65; crystals are trigonal (commonly appearing hexagonal).
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Physical properties
Hardness 7 Mohs; vitreous luster; translucent purple-to-gray druzy crystals on a darker matrix, with conchoidal fracture and no cleavage. Specific gravity is about 2.65; crystals are trigonal (commonly appearing hexagonal).
Formation & geological history
Forms when silica-rich hydrothermal fluids or volcanic cavities deposit tiny quartz crystals, with trace iron producing purple color. Most specimens formed in geologically young-to-ancient volcanic geodes, especially in Brazil, Uruguay, Mexico, and Africa.
Uses & applications
Used as a decorative mineral, jewelry, cabochons, crystal displays, and lapidary material; druzy surfaces are commonly mounted in pendants and rings.
Geological facts
“Druzy” describes a coating of many minute crystals rather than a separate mineral. Color intensity can fade with prolonged heat or strong sunlight.
Field identification & locations
Identify by sparkly microcrystals, quartz hardness, glassy luster, and purple coloration; it should scratch glass but not be scratched by a steel knife. Common pieces sell for about $5–$30, while larger, vividly colored or well-mounted specimens may reach $50–$150.
