Amethyst

A variety of Quartz, amethyst’s bold purple has contributed to its reputation over the centuries as a gem favoured by royalty and the clergy.  
One possible source for it's name is the popular belief is that it comes from the Ancient Greek “a-”, meaning “not”, and “methustos”, meaning “intoxicated” — 
a reference to the belief that the gem protected its owner from drunkenness, leading to goblets being carved out of this precious material.
Amethysts range in colour from vivid purple to shades of mauve, violet and lilac, often with flashes of pinkish-red and blue.