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 refuse to do. Kerans dismisses his demands but is able to manipulate Peng into the release of the Petty Officers; meanwhile, as talks progress he has the ship patched up and its engines restored. After some subtle alterations to the ship's outline to try to disguise her, "Amethyst" slips her cable and heads downriver in the dark following a local merchant ship, which "Amethyst" uses to show the way through the shoals and distract the PLA. When the shore batteries finally notice the frigate escaping downriver, the merchantman receives the brunt of the PLA artillery and catches fire, while "Amethyst"