Ametrine, also known by its trade name as trystine or as bolivianite, is a naturally occurring variety of quartz. It is a mixture of amethyst and citrine with zones of purple and yellow or orange. Almost all won ametrine available commercially in Bolivia, but there are deposits being exploited in Brazil and India. The color of the zones are visible in Ametrien by the various oxidation states of iron in the crystal. The various oxidation states occur as a result that there is a temperature gradient across the crystal during its formation Artificial Ametrien can be created by differential thermal treatment of amethyst. Legend has it that ametrine was first introduced in Europe by a conquistador gifts to the Spanish queen, after a mine in Bolivia as a dowry when he married a princess from the indigenous tribe Ayoreos. Most Ametrien in the low price segment can be assumed to arise from synthetic material. Since 1994 a Russian laboratory has perfected the industrial production of two-tone quartz crystals which are subsequently irradiated to bring out the typical ametrine colors. Green - yellow gold or blue ametrine not occur naturally.