SCIENTIFIC PROPERTIES

Scientific Properties:
Mohs Hardness of 7 with a trigonal crystal structure.

Also known as trystine or by it's trade name bolivianite, it is a naturally occurring variety of quartz. It is a "mixture" of amethyst and citrine with zones of purple and of yellow or orange, but yet a crystal of it's own, not just a mixture of it's two cousins. Most all commercially available ametrine is minded in Bolivia, although there are deposits being exploited in Brazil as well as India.

The different colors visible within ametrine are due to differing oxidation states of iron within the crystal. The different oxidation states occur due to a temperature gradient across the crystal during it's formation.

In order for the Iron to produce both colors within the same crystal, very specific conditions have to be present. Not only does one area of the crystal have to be exposed to more heat, while another section is slightly cooler; this dual temperature condition has to remain stable during the entire growth cycle of the crystal.

Geologists theorize that a deep vent within the Anahi mine created just the right amount of heat, flowing in just the right direction to cause one area of the forming crystals to stay "hotter" than the rest. Creating the perfect balance to form ametrines. Otherwise, these magical gems would have become Amethysts or Citrines.

Only two places on the entire planet had just the right circumstances to form Ametrine Crystals. The Anahi Mine in Bolivia and the Hyderabad Mine in India. The Bolivian mine yields about 90% of ametrine being marketed today.

In 1999 a new area of the mine was opened near Pozo Rico and a huge cavern of Ametrine crystals was discovered. This crystal covered cave measures 4 meters x 3 meters x 1 meter. India's Ametrine is primarily Amethyst with small Citrine zones and lack the rich bi-coloring found in the Bolivian specimens.

Today the bi-colors of the Ametrine are extremely popular in the jewelry trade. Despite its rarity, this special Quartz crystal remains very reasonably priced. Cutters have developed new faceting techniques and elongated rectangles shapes to show off this gem's delightful duality. Artificial ametrine can be created by differential heat treatment of amethyst.