Stone information and mining
Transparent, bicolored quartz with the colors of both amethyst and citrine in the same gem is called ametrine or amethyst-citrine. The contrasting colors give it an intriguing appearance.
Fine ametrine shows medium dark to moderately strong orange, and vivid to strong purple or violetish purple. Larger gems, usually those over 5 carats, tend to show the most intensely saturated hues. Dealers look for an attractive half-and-half distribution of each color, with a sharp boundary between the two colors at the center of the fashioned gemstone.
Ametrine is often cut as a rectangular step cut because that style nicely displays the bicolor effect. Cutters try to emphasize both colors equally. Cutters sometimes fashion ametrines as mixed cuts or brilliant cuts and use internal reflections to mingle the amethyst and citrine colors. Ametrine is also popular in free-form or fantasy cuts. There's only one commercial source of natural ametrine: a deposit in eastern Bolivia, close to the Brazilian border. Legend has it that a Spanish conquistador discovered the location in the 1600s, but it was lost for more than three centuries. Ametrine began appearing on the market again during the 1970s. The mine, the Anahi, also produces natural amethyst and citrine.
Legend & Lore
The world's only commercial source of ametrine is the Anahi mine in southeastern Bolivia. Legend has it that a Spanish conquistador discovered the mine's location in the 1600s and introduced the gem to Europeans when he presented several specimens to his queen. The mine had been given to him as a dowry when he married a native princess named Anahi. After that, the mine was lost for more than three centuries. Rediscovered in the 1960s, the mine's ametrine began appearing on the market again during the 1970s. Today the mine, named Anahi for the legendary princess, also produces natural amethyst and citrine.
Ametrine is a bicolor gem that's highly prized when it displays an attractive balance between its most desirable amethyst and citrine shades.
Ametrine can be safely cleaned with warm, soapy water. Ultrasonic cleaners are usually safe except in the rare instances where a stone is dyed or treated by fracture filling. Steam cleaning is not recommended, and ametrine should not be exposed to heat.
This information was excerpted from GIA's Gem Encyclopedia with permission from GIA.