Amethyst
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/14730981@N08">James Petts</a> from London, England (CC BY-SA 2.0)
Mineral NameAmethyst
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak ColorWhite
CleavageNone
FractureConchoidal
Specific Gravity2.65
Colorspurple, violet, white
TransparencyTransparent to translucent
Type LocalityBrazil
Mineral GroupSilicates
Usesjewelry, collector, decorative
Associated Mineralschalcedony, calcite, goethite
Raritycommon
Description
The image displays a cluster of amethyst crystals, exhibiting various shades of purple from deep violet to lighter lavender, with some clear or white bases. The crystals are well-formed, showing typical hexagonal prism faces terminating in pyramidal points.
Geological Context
Amethyst forms in hydrothermal veins or within the cavities of volcanic rocks (geodes) where silica-rich fluids containing trace amounts of iron are subjected to natural irradiation.
