A purple variety of the mineral quartz, the finest amethyst colour is strong reddish-purple to purple with no visible colour zoning. Coloured by Iron, the shades of Amethyst occur in transparent pastel roses to deep purples. Like many other gemstones, the quality of Amethyst varies according to its source. The best varieties of amethyst can be found in Siberia, Sri Lanka, Brazil and the far East.