mineral
Amethyst
Quartz (Silicon Dioxide, SiO2 with iron impurities)
Hardness of 7 on the Mohs scale, purple to violet color, vitreous luster, hexagonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.
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Physical properties
Hardness of 7 on the Mohs scale, purple to violet color, vitreous luster, hexagonal crystal system, conchoidal fracture with no true cleavage, specific gravity of 2.65.
Formation & geological history
Forms within gas cavities (vesicles) in volcanic rocks or as linings in hydrothermal veins where silica-rich solutions cool and crystallize over long geological timescales.
Uses & applications
Widely used in jewelry as a gemstone, spiritual and metaphysical practices, decorative carvings, and mineral collecting.
Geological facts
Amethyst was once considered one of the cardinal gemstones of high value until large deposits were discovered in Brazil. Its purple color is caused by irradiation and trace amounts of iron.
Field identification & locations
Identified by its distinct purple color, crystal habit, and a Mohs hardness that easily scratches glass. Common sources include Brazil, Uruguay, Zambia, and the United States.
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