Amethyst of synthetic quartz is used. Treated amethyst is produced by gamma ray, X-ray or electron beam irradiation of clear quartz (rock crystal) which has been first doped with ferric impurities. On exposure to heat, the irradiation effects can be partially cancelled and amethyst generally becomes yellow or even green, and much of the citrine, cairngorm, or yellow quartz of jewelry is said to be merely "burnt amethyst". The Greek word "amethystos" may be translated as "not drunken", from Greek "a-", "not" + "methustos", "intoxicated". Amethyst was considered to be a strong antidote against drunkenness, which is why wine goblets were
Amethyst in abundance from the state of Minas Gerais in Brazil where it occurs in large geodes within volcanic rocks. Many of the hollow agates of southwestern Brazil and Uruguay contain a crop of amethyst crystals in the interior. Artigas, Uruguay and neighboring Brazilian state Rio Grande do Sul are large world producers exceeding in quantity Minas Gerais, as well as Mato Grosso, Espirito Santo, Bahia, and Ceará states, all amethyst producers of importance in Brazil. It is also found and mined in South Korea. The largest opencast amethyst vein in the world is in Maissau, Lower Austria. Much fine amethyst