Amethyst cathedral has quartz inclusions along the base and sides. Amethyst has been a prized gem for centuries. Amethysts are the most valuable variety of quartz, and were one of the first gemstones used by people around the world. The Greeks believed that drinking wine from an amethyst cup would prevent intoxication. Royalty has also favored the purple gemstone, and at one time amethysts were reserved for royalty alone. Amethysts are also found in the British Crown jewels. Approximately 7.5 inches x 8.5 inches x 5 inches. 6.6 kg.