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 state had wrongly invaded Chinese national waters and had fired upon the PLA first. Because the communists (and later the People's Republic of China) did not acknowledge any treaties between the previous Chinese government and the British, they insisted that it was illegal for "Amethyst" to cruise in the Yangtze river. On 30 July 1949 "Amethyst" slipped her chain and headed downriver in the dark, beginning a dash for freedom running the gauntlet of guns on both banks of the river. She followed the passenger ship "Kiang Ling Liberation" in the hope that the observers ashore would be confused and