Amethyst of synthetic quartz is used. Treated amethyst is produced by gamma ray, X-ray or electron beam irradiation of clear quartz (rock crystal) which has been first doped with ferric impurities. On exposure to heat, the irradiation effects can be partially cancelled and amethyst generally becomes yellow or even green, and much of the citrine, cairngorm, or yellow quartz of jewelry is said to be merely "burnt amethyst". The Greek word "amethystos" may be translated as "not drunken", from Greek "a-", "not" + "methustos", "intoxicated". Amethyst was considered to be a strong antidote against drunkenness, which is why wine goblets were
SS Empire Amethyst to lose her pursuer at 00:24 on 13 April by making a sharp turn. At 01:27 hrs, Kölle ordered his engines stopped to try to ascertain where "Empire Amethyst" was. Kölle decided to head in the direction that "Empire Amethyst" was generally heading and by 04:30 had found her again. At 05:52, Kölle aimed the first of two torpedoes at "Empire Amethyst", which hit under the bridge. The second exploded forward of the engine room and she exploded in a mass of flames that were visible from away. "Empire Amethyst" sank with the loss of all 47 crew at .