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 distress call from the American SS "Delvalla" which had been torpedoed by "U-154" and was sinking. "Prince Henry" headed for the reported position of the "Delvalla" and a Catalina aircraft was despatched. The survivors were taken aboard "Prince Henry". "U-154" spotted "Empire Amethyst" again at 11:42 hrs; she was again under escort by "Prince Henry" but at 16:00 hrs the escort had been lost. As he was short of torpedoes, Kapitän Kölle decided to attack from the surface. The chase began at 20:00 hrs with "Empire Amethyst" zig-zagging but generally following a heading of 110° towards Trinidad. "Empire Amethyst" managed