mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 (Mohs), Color: Purple to violet, Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs), Color: Purple to violet, Luster: Vitreous (glassy), Crystal Structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins and hollow cavities (geodes) within igneous rocks, often where silica-rich minerals crystallize at medium-to-low temperatures. Its purple color comes from irradiation and iron impurities.
Uses & applications
Widely used for jewelry (faceted or cabochon), ornamental carvings, crystal healing, and as home decor/specimens for collectors.
Geological facts
Amethyst is the birthstone for February. Ancient Greeks believed it could prevent intoxication; the word comes from the Greek 'amethystos,' meaning 'not drunken.'
Field identification & locations
Look for its signature purple color and lack of cleavage (breaks like glass). Commonly found in Brazil, Uruguay, and Africa. Collectors should check for pleochroism and natural inclusions.
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