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) of York to the Netherlands and later participated in the evacuation of the force following the campaign's collapse. On 18 December she and recaptured the brig "Jenny". Eleven days after that, "Amethyst" and "Beaulieu" recaptured the ships "Dauphin", "Cato", "Cabrus", and "Nymphe". On 29 December "Amethyst" captured the French privateer brig "Aventurier" (or "Avanture"). "Aventurier", out of Lorient, was armed with 14 guns and had a crew of 75 men. One month earlier, on 29 November, "Aventurier" had captured the American ship "Cato" and taken her master, John Parker, and his crew prisoner. When "Amethyst" captured "Aventurier" Cooke freed the