Amethyst is a form of the mineral quartz. As such it is related to citrine, the yellow form of quartz, and to rock crystal, the colourless variety. Amethyst is found in clear purple, mauve or deep violet and looks beautiful when cut and polished and set in jewellery.
Amethyst beads can be found in Anglo-Saxon graves in England. In general it is geographically quite widespread, but fine, clear specimens suitable for cutting as ornamental stones are quite rare. These crystals tend to occur in caves of mineral and granite rocks, or as a lining in an agate geode. A particularly huge amethyst grotto from near Santa Cruz in south Brazil was exhibited at the Dusseldorf exhibition of 1902.
Much good quality amethyst is found in Russia, and there is also a substantial amount in India and Sri Lanka, chiefly in the form of pebbles. It can also be found in many of the hollow agates of Brazil and Uruguay, and at several locations in the United States, including Texas, Pennsylvania and North Carolina.
Amethyst was so popular with the Russian Empress Catherine the Great that she sent thousands of miners into the Urals to search for it. It is the most popular stone for Christian ornaments - it is found in the lavish Italian Papal Ring from the 15th Century, on show in the Jewellery Museum in Pforzheim, and in many Bishops’ rings.