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
Amethyst Incident if she came under fire from the shore batteries at Woosung. To achieve this she had moved up the Yangtze during the night, at action stations. Fortunately for the British, "Amethyst" was not spotted by the shore batteries and the two ships then proceeded down river until at 0715 they stood down from action stations and after clearing the river mouth arrived at the Saddle Islands at 1200 hrs to anchor and transfer much needed oil and stores. After a short stay at anchor, "Concord" lent "Amethyst" sailors to fill gaps in her ship's company and the two ships set