Amethyst and it can not be differentiated with absolute certainty without advanced gemmological testing (which is often cost-prohibitive). There is one test based on "Brazil law twinning" (a form of quartz twinning where right and left hand quartz structures are combined in a single crystal) which can be used to identify synthetic amethyst rather easily. It is possible to synthesize twinned amethyst, but this type is not available in large quantities in the market. Single-crystal quartz is very desirable in the industry, particularly for keeping the regular vibrations necessary for quartz movements in watches and clocks, which is where a lot
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