mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous/Glassy, Crystal system: Hexagonal (Trigonal), Cleavage: None (conchoidal fracture), Transparency: Transparent to translucent
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Physical properties
Hardness: 7 (Mohs scale), Color: Purple to violet, Luster: Vitreous/Glassy, Crystal system: Hexagonal (Trigonal), Cleavage: None (conchoidal fracture), Transparency: Transparent to translucent
Formation & geological history
Forms in hydrothermal veins or cavities (geodes) within igneous rocks. The purple color is caused by natural irradiation of trace trivalent iron (Fe3+) within the crystal lattice.
Uses & applications
Highly valued as a gemstone in jewelry (rings, necklaces, earrings), ornamental carvings, and popular among crystal collectors for metaphysical and aesthetic purposes.
Geological facts
Until the 18th century discovery of large deposits in Brazil, amethyst was considered a 'Cardinal Gem' and was as expensive as diamonds and rubies. It is the birthstone for February.
Field identification & locations
Identify by its characteristic purple color, hardness (it will scratch glass), and lack of cleavage. Commonly found in Brazil, Uruguay, Zambia, and South Korea.
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Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Schist
Schist
Metamorphic
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock
Granite
Granite (Phaneritic intrusive igneous rock)
igneous