Amethyst
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Mineral NameAmethyst
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorspurple, violet
Transparencytransparent
Type LocalityBrazil, Uruguay, Zambia
Mineral GroupSilicates
Usesjewelry, ornamental, collector
Associated Mineralscalcite, goethite, hematite, other quartz varieties
Raritycommon
Description
Amethyst is a purple variety of quartz, typically forming prismatic crystals in druzy aggregates or geodes, often with distinct color zoning.
Geological Context
It forms in hydrothermal veins and cavities within igneous rocks (especially basalts) and some metamorphic rocks, crystallizing from silica-rich fluids at relatively low temperatures.
