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) kept "Amethyst" from joining the action. The British brought "Dédaigneuse" into Royal Navy service as HMS "Dedaigneuse". Later on 28 January "Sirius" and "Amethyst" captured the Spanish Letter of Marque "Charlotta" (or "Carlotta") of Ferol, 16 hours out of Ferol on her way to Curaçao. The capture took place about six or seven leagues from Cape Belem in Galicia. The hired armed cutter "Earl St Vincent" shared in the capture. The next day captured the Spanish privateer "Intrepido Cid". "Amethyst" and "Sirius" shared in the prize money by agreement. On 16 March, "Amethyst" encountered and captured "Nostra Signora del Carmen",