Amethyst
Image: <a href="//commons.wikimedia.org/wiki/User:Szilas" title="User:Szilas">Szilas</a> (CC0)
Mineral NameAmethyst
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorspurple, violet
Transparencytransparent
Type LocalityŠtiavnica, Slovakia
Mineral GroupSilicates
Usesjewelry, ornamental, collector
Associated Mineralscalcite, zeolites, agate, chalcedony
Raritycommon
Description
The image displays two specimens of amethyst, characterized by clusters of vibrant purple, terminated quartz crystals growing on a white to brownish matrix.
Geological Context
Amethyst forms in hydrothermal veins, geodes, and volcanic rocks, where silica-rich fluids deposit quartz crystals. The characteristic purple color is attributed to irradiation and trace iron impurities within the quartz lattice.
