Description
Ametrine, also known as trystine or by its trade name 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, but there are deposits in Brazil and India that are exploited. The color of the zones visible in ametrine is due to the different oxidation states of iron within the crystal. These different oxidation states occur due to a temperature gradient across the crystal during its formation. Artificial ametrine can be created by differential heat treatment of amethyst. Legend has it that ametrine was first introduced to Europe by a conquistador as a gift to the Spanish queen, who had a mine in Bolivia as his dowry when he married a princess from the indigenous Ayoreos tribe. Most ametrine in the low-priced range can be assumed to originate from synthetic material. Since 1994, a Russian laboratory has perfected the industrial production of two-tone quartz crystals, which are then irradiated to produce the characteristic ametrine colors. Greenish-yellow or gold-blue ametrine does not occur naturally.
