mineral
Amethyst cluster
Amethyst, purple quartz (SiO₂)
AI-generated identification · may be incorrectHardness 7 Mohs; purple to violet crystals with vitreous luster, hexagonal crystal structure, and no true cleavage. The specimen appears to be a small natural crystal cluster, possibly on a darker matrix.
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Physical properties
Hardness 7 Mohs; purple to violet crystals with vitreous luster, hexagonal crystal structure, and no true cleavage. The specimen appears to be a small natural crystal cluster, possibly on a darker matrix.
Formation & geological history
Amethyst forms when silica-rich fluids crystallize in cavities, commonly in volcanic rocks; its purple color comes from trace iron and natural irradiation. Such deposits formed across many geological ages, notably in Brazil and Uruguay.
Uses & applications
Used in jewelry, decorative objects, and mineral collections; larger clusters are popular display pieces.
Geological facts
Amethyst is the purple variety of quartz and has been prized as a gemstone since antiquity.
Field identification & locations
Identify by its purple color, glassy luster, and hardness; it commonly occurs in geodes and veins, especially in Brazil and Uruguay. Avoid assuming color alone is diagnostic, since dyed materials exist.
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