Amethyst is a translucent variety of quartz in a violet colored gemstone. The name is derrived from the Ancient Greek who believed the stone protected its owner from drunkenness. Both ancient Greeks and Romans believed this and made drinking vessels out of it in the beleif that it would prevent intoxication. Green amethyst is techically unrelated to amethyst as it's actually called prasiolite: a green variety of quartz. Amethyst is the birthstone for February.