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 Mountain of being of regional extent as previously thought, these beds are quite limited in extent. The localized distribution of both petrified wood-bearing and fossil-forest beds reflects restricted areas that were buried by individual lahars. In regard to these fossil forests and other fossils, collecting of fossils in Yellowstone National Park is illegal. In addition, visitors should stay on marked and maintained trails. Amethyst Mountain Amethyst Mountain, el. is the highest peak and central part of a northwest – southeast trending ridge that lies between the Lamar River to the northeast and Deep Creek to the southwest within Park County, Wyoming.