Amethyst
Image: Photo by and (c)2015 Derek Ramsey (<a href="https://en.wikipedia.org/wiki/User:Ram-Man" class="extiw" title="en:User:Ram-Man">Ram-Man</a>) (CC BY-SA 4.0)
Mineral NameAmethyst
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.65
Colorspurple, violet, reddish-purple
Transparencytransparent
Type LocalityBrazil, Uruguay, Russia, Zambia, Canada, USA
Mineral GroupSilicates
Usesjewelry, collector, ornamental
Associated Mineralscalcite, zeolites, agate, other quartz varieties
Raritycommon
Description
This specimen displays a cluster of deep purple to reddish-purple amethyst crystals, exhibiting well-formed prismatic to pyramidal habits with a distinct vitreous luster.
Geological Context
Amethyst forms in hydrothermal veins, vugs, and geodes within igneous rocks, particularly basaltic lavas. Its characteristic purple color is attributed to irradiation of iron impurities within the quartz crystal lattice.
