Amethyst is a purple variety of quartz. Amethyst is found throughout the world and can vary in colour from lilac to deep violet and even green. The Ancient Greeks believed that amethyst protected people from intoxication. Amethyst is the birthstone for February.
Until the 18th century, amethyst was included in the cardinal, or most valuable, gemstones (along with diamond, sapphire, ruby, and emerald), but since the discovery of extensive deposits in locations such as Brazil, it is now considered a semiprecious stone.