Amethyst is a purple variety of quartz (silicon dioxide). Its name, derived from Greek, meaning "not drunk". It was indeed considered in antiquity as a talisman against drunkenness. Its color is due to the presence of iron. Classic jewelery, it is the most popular group of quartz and is part of gemstones. It comes mainly from Brazil, Madagascar, Uruguay, Zambia, Burma, Canada, USA, India, Mexico, Namibia, Russia, Sri Lanka.