Amethyst
Image: James St. John (CC BY 2.0)
Mineral NameAmethyst
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorspurple, violet, lavender
Transparencytransparent
Type LocalityBrazil, Uruguay, Zambia, Russia, Canada, USA
Mineral GroupSilicates
Usesjewelry, ornamental, collector
Associated Mineralsquartz, calcite, zeolites, hematite, goethite
Raritycommon
Description
This image displays a cluster of vibrant purple amethyst crystals, exhibiting their characteristic hexagonal prismatic habit and vitreous luster. Some crystals show reddish-brown inclusions, likely hematite as indicated by the image title.
Geological Context
Amethyst forms in hydrothermal veins, geodes, and cavities within volcanic rocks, where silica-rich fluids containing trace amounts of iron are subjected to natural irradiation. It is a variety of quartz, with its purple color attributed to iron impurities and natural irradiation.
