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 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