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 Half an hour later her signals ceased, though she was making a second attempt to take the "Amethyst" in tow, having turned downstream again. This attempt also failed and she sustained further damage and casualties during which her steering was affected. She therefore had to continue downstream out of the firing area with 10 men killed and 23 wounded. "Amethyst" was re-floated just after midnight, on 21 April, after lightening the ship, and she moved up river. The Assistant British Naval Attaché, Lieutenant Commander John Kerans, joined the ship on 22 April after he had dealt with all the wounded