mineral
Amethyst (purple quartz crystal cluster)
Quartz, SiO₂; amethyst is purple, iron-bearing quartz
AI-generated identification · may be incorrectMohs hardness 7; purple to nearly black with vitreous luster and hexagonal crystal structure. Quartz has no cleavage and shows conchoidal fracture; the specimen appears to include blocky crystal faces.
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Physical properties
Mohs hardness 7; purple to nearly black with vitreous luster and hexagonal crystal structure. Quartz has no cleavage and shows conchoidal fracture; the specimen appears to include blocky crystal faces.
Formation & geological history
Forms as quartz crystals in cavities and veins, commonly in volcanic rocks, as silica-rich fluids cool. Amethyst deposits range from ancient to geologically recent; this specimen’s precise age and locality cannot be determined from the image.
Uses & applications
Used for jewelry, ornamental carvings, display specimens, and collecting; lower-grade material is also used decoratively.
Geological facts
Amethyst’s purple color is associated with iron impurities and natural irradiation; heating can change its color toward yellow or brown.
Field identification & locations
Look for purple coloration, glassy luster, and quartz-like hardness; common sources include Brazil, Uruguay, Zambia, and Mexico. The dark color and lighting make exact identification and quality assessment uncertain.
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