Ametrine, also known as Trystine or by its trade name 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 commercially available Ametrine is mined in Bolivia.
The colour of the zones visible within Ametrine are due to differing oxidation states of Iron within the crystal. The Citrine segments have oxidized Iron while the Amethyst segments are unoxidized. The different oxidation states occur due to there being a temperature gradient across the crystal during its formation. Artificial Ametrine is created from natural Citrine through beta irradiation (which creates an Amethyst portion), or from an Amethyst that is turned into Citrine through differential heat treatment.
This gem only exists naturally in Bolivia, where it comes from the Ricón del Tigre area, from the Anahí mine.
Legend has it that Ametrine was first introduced to Europe by a Conquistador's gifts to the Spanish Queen in the 1600s, after he received a mine in Bolivia as a Dowry when he married a Princess from the native Ayoreos Tribe.
