Very rare group of dark purple Amethyst crystals, showing modifying faces including "c-face." Crystals from the Four Peaks Arizona mine are almost always with dull luster which is the case here. But the size and form of this group makes it a museum quality specimen from the premier US gem Amethyst locality. Buyer receives a copy of the Gemological Inst. of America's Gems and Gemology article on Four Peaks by John Koivula and Jack Lowell, (fall of 2004) Check our Amethyst Gemstone section for faceted gems from the mine.