relatetorocks:Amethyst is a variety of quartz (SiO2). The violet color is believed to come from iro
relatetorocks:Amethyst is a variety of quartz (SiO2). The violet color is believed to come from iron impurities (and possibly other trace elements). The vast majority of amethyst you see in stores, etc. comes from eastern South America (mainly Brazil) where it commonly found formed within open spaces (i.e. vugs, gas bubbles, tubes, etc.) within the Paraná flood basalt. -- source link