Amethyst element impurities), and the presence of trace elements, which result in complex crystal lattice substitutions. The hardness of the mineral is the same as quartz, thus it is suitable for use in jewelry. Amethyst occurs in primary hues from a light pinkish violet to a deep purple. Amethyst may exhibit one or both secondary hues, red and blue. The best varieties of amethyst can be found in Siberia, Sri Lanka, Brazil and the far East. The ideal grade is called "Deep Siberian" and has a primary purple hue of around 75–80%, with 15–20% blue and (depending on the light source)
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 .