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 (1799) the Île de France some nine weeks earlier and was sailing for Bordeaux with a cargo of cotton, coffee, tea, sugar, indigo, and the like. Still in company with "Nymphe", "Amethyst" captured "Julius Pringle" and recaptured "Active" (4 March) and "Amity" (21 March). Then on 31 March, "Amethyst", with "Nymphe", captured the French privateer "Mars". "Mars" was armed with twenty 12-pounder guns and two 36-pounder obusiers, and carried a crew of 180 men. Cooke described her as being "one of the finest Privateers fitted out of Bourdeaux." The British took "Mars" into service as . "Amethyst" also captured a valuable