Amethyst is not primarily defined by carat weight; this is different to most gemstones where the carat weight exponentially increases the value of the stone. The biggest factor in the value of amethyst is the color displayed. The highest grade amethyst (called "Deep Russian") is exceptionally rare and therefore, when one is found, its value is dependent on the demand of collectors. It is, however, still orders of magnitude lower than the highest grade sapphires or rubies (padparadscha sapphire or "pigeon's blood" ruby). Amethyst Amethyst is a violet variety of quartz. The name comes from the Koine Greek ἀμέθυστος "amethystos" from
SS Empire Amethyst at Belfast to allow a crew member to be discharged through illness and a replacement to be taken on board. On reaching Freetown, "Empire Amethyst" sailed for New Orleans. In mid-April 1942, "Empire Amethyst" left New Orleans bound for Freetown carrying a cargo of 12,000 tons of motor spirit. Her intended route took her via the Lesser Antilles and then across the Atlantic to Freetown. "Empire Amethyst" was spotted by the crew of on 12 April 1942. The U-boat captain, Walther Kölle, believed that she was being escorted by and did not attack. At 03:02 hrs "Empire Amethyst" received a