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
HMS Amethyst (1903) HMS Amethyst (1903) HMS "Amethyst" was a third-class protected cruiser of the "Topaze" class of the Royal Navy. She was launched in 1903, served during World War I at the Dardanelles and Gallipoli, in the Mediterranean and the South Atlantic. She was sold for scrap in 1920. She was laid down in January 1903 at Armstrong, Elswick, was launched on 5 November 1903 and was completed in March 1905. Until "Amethyst" was built, the largest warships fitted with steam turbines were destroyers. Their use in "Amethyst" reduced overall range at 10 knots by , but increased it by at 20