Amethyst Amethyst Amethyst is a violet variety of quartz. The name comes from the Koine Greek ἀμέθυστος "amethystos" from ἀ- "a-", "not" and μεθύσκω "methysko" / μεθύω "methyo", "intoxicate", a reference to the belief that the stone protected its owner from drunkenness. The ancient Greeks wore amethyst and carved drinking vessels from it in the belief that it would prevent intoxication. Amethyst is a semiprecious stone often used in jewelry and is the traditional birthstone for February. Amethyst is a purple variety of quartz (SiO) and owes its violet color to irradiation, iron impurities (in some cases in conjunction with transition
Amethyst lapidary involves correctly cutting the stone to place the color in a way that makes the tone of the finished gem homogeneous. Often, the fact that sometimes only a thin surface layer of violet color is present in the stone or that the color is not homogeneous makes for a difficult cutting. The color of amethyst has been demonstrated to result from substitution by irradiation of trivalent iron (Fe) for silicon in the structure, in the presence of trace elements of large ionic radius, and, to a certain extent, the amethyst color can naturally result from displacement of transition elements