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
Yangtse Incident: The Story of H.M.S. Amethyst rescue attempt by two other ships also comes under heavy fire and has to be aborted. Fifty-four of "Amethyst"s crew are dead, dying or seriously wounded, while others deteriorate from the tropical heat and the lack of essential medicines, including the ship's captain, who dies of his wounds. An attempt to evacuate the wounded is only partially successful - the officers of the "Amethyst" become aware that two petty officers have been captured by the PLA and are being held at a nearby military hospital. Lieutenant Commander John Kerans (Richard Todd), a naval attaché in nearby Nanking, is ordered to