Amethyst is a purple variety of quartz (SiO2) that owes its violet color to irradiation, iron impurities and the existence of trace elements. It occurs in primary hues from a light pinkish violet to a deep purple and may exhibit one or both secondary hues, red and blue.
Natural amethyst is dichroic in reddish violet and bluish violet, but when heated, turns yelloworange, yellow-brown, or dark brownish. It may resemble citrine, but loses its dichroism, unlike genuine citrine. On partial heating, amethyst can result in ametrine.
Synthetic amethyst is created by gamma-ray, x-ray or electron beam irradiation of clear quartz that is initially treated with ferric impurities. On exposure to heat, the irradiation effects can be partially cancelled and amethyst generally becomes yellow or even green.
Synthetic amethyst is made to imitate the best quality amethyst whose chemical and physical properties are similar to that of natural amethyst.
Upon heating, Amethyst changes its colour. Smoky stones are transformed at temperatures of as little as 250 degrees to a shining yellow to brownish-red, whilst those with a high degree of
transparency, become yellow or colourless at 400 degrees. Some amethysts fade almost to colorless in daylight, but can be re-colored by means of exposure to radium radiation.
Brandberg Amethyst is a unique and extraordinary blend of Amethyst, Clear and Smoky Quartz together in one exceedingly high-vibrational crystal.
Chevron Amethyst displays v-shaped chevrons of deep purple and white Quartz that seep into beautiful layers.
Cacoxenite in Amethyst mingles dark brown to yellow tufts of Cacoxenite, a phosphate mineral, with the host crystal Amethyst.
Ametrine is a combination of Amethyst and Citrine within the same crystal. It is partially purple and partially yellow or orange, with the color zones often sharply divided.
Rutilated Amethyst is a rare form of Amethyst which contains brownish crystals of Goethite, an iron hydroxide mineral.
Amethyst Quartz is mixture of Amethyst and Milky Quartz or clear quartz. It is purple on top and white or clear on the bottom. It may also be banded purple and white.
Cactus Quartz is a form of Quartz, usually Amethyst, Citrine, or a combination of the two, that contains a large crystal or crystals overgrown with a layer of spiky smaller crystals.
Canadian Amethyst is Amethyst with coating of the red Hematite under the crystal surface.
Lavender Amethyst is Pale purple variety of Amethyst and Veracruz Amethyst is tall and