mineral
Amethyst cluster
Quartz (SiO₂), purple variety; trigonal crystal system
AI-generated identification · may be incorrectMohs hardness 7; translucent pale-to-deep purple crystals with a vitreous luster, commonly forming six-sided prisms. No cleavage; uneven to conchoidal fracture. The image shows a natural crystal cluster, possibly on a pale matrix.
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Physical properties
Mohs hardness 7; translucent pale-to-deep purple crystals with a vitreous luster, commonly forming six-sided prisms. No cleavage; uneven to conchoidal fracture. The image shows a natural crystal cluster, possibly on a pale matrix.
Formation & geological history
Amethyst forms as quartz crystals grow in cavities and veins, often in volcanic rocks from silica-rich fluids. Specimen age depends on locality and can range from millions to hundreds of millions of years.
Uses & applications
Used in jewelry, decorative objects, and mineral collections; lower-grade material is also used for carvings and ornamental stone.
Geological facts
Purple color is generally associated with trace iron and natural irradiation. Heating can change amethyst’s color, sometimes producing yellow-orange citrine-like material.
Field identification & locations
Commonly found in geodes and volcanic cavities, notably in Brazil, Uruguay, and Zambia. Identify by purple quartz crystals with hardness 7; value varies with color, clarity, size, and damage.
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