mineral
Amethyst
Silicon dioxide with iron impurities (SiO2 + Fe3+)
Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous/glassy, Crystal structure: Trigonal (Hexagonal prisms), Cleavage: None (Conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous/glassy, Crystal structure: Trigonal (Hexagonal prisms), Cleavage: None (Conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or as linings inside volcanic geodes. The purple color comes from natural irradiation of trace amounts of iron within the quartz crystal lattice.
Uses & applications
Primarily used as a gemstone in jewelry (rings, necklaces, earrings) and as decorative specimens for mineral collectors.
Geological facts
Amethyst was considered a 'Precious Stone' alongside Diamond, Sapphire, Ruby, and Emerald until large deposits were found in Brazil in the 19th century. Its name comes from the Greek word 'amethystos', meaning 'not intoxicated'.
Field identification & locations
Identify by its distinct purple hue, hexagonal crystal shape (if present), and ability to scratch glass. Commonly found in Brazil, Uruguay, and Africa.
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Gypsum (variety Selenite or Alabaster)
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Mineral
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Mineral/Rock
Granite
Granite (Phaneritic intrusive igneous rock)
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