Amethyst refers to purple and bluish-violet varieties of quartz. The name derives from the Ancient Greek words for "not" and "intoxication". It was believed that the mineral protected the wearer from drunkenness, intoxication, and seduction. Amethyst has been gathered and mined since Neolithic times. The mineral's hardness makes it well-suited for use in jewelry. Amethyst is the birthstone for February.