Amethyst even if the iron concentration is low. Natural amethyst is dichroic in reddish violet and bluish violet, but when heated, turns yellow-orange, yellow-brown, or dark brownish and may resemble citrine, but loses its dichroism, unlike genuine citrine. When partially heated, amethyst can result in ametrine. Amethyst can fade in tone if overexposed to light sources and can be artificially darkened with adequate irradiation. Amethyst was used as a gemstone by the ancient Egyptians and was largely employed in antiquity for intaglio engraved gems. The largest Ancient Egyptian amethyst mines are located at Wadi el-Hudi and those mines may be the
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 .