The name "amethyst" refers specifically to the purple variety of the mineral quartz. Quartz in other colours such as pink, green and black are not amethyst.
The purple colour of this mineral comes from impurities of iron.
The belief that amethyst has the ability to counter the effects of alcohol came about because its colour was once likened to wine.
Having been named "amethystos" from the Greek for "not" and "intoxicate" a myth was born.
The colour of amethyst will gradually if exposed to UV light.
Most of the world's finest amethyst comes from South America.