LEARN MORE ABOUT TANZANITE STONE
Tanzanite was discovered in 1967, at the foot of Mount Kilimanjaro in Tanzania (which gave the stone its name). Tanzanite is a pleochroic gemstone, meaning it can appear to have different colors under different light. In natural light, the stone resembles Sapphire in color, however in fluorescent light, it is closer to Amethyst in color. They are naturally trichroic, meaning the show blue, red-violet and yellow-green colors depending on the light on its three crystal axes in colored stones.
TANZANITE Gemstone Attributes
|Color||Violetish Blue - Blue|
|Refractive Index||1.691 - 1.700|
|Birefringence||0.008 - 0.013|
|Mohs Hardness||6.0 - 7.0|
Tanzanite Stone has seen a rapid increase in popularity in the last few years. Its mineral name is Zoisite and is naturally reddish brown in color, it is through heat treatment that it achieves its beautiful blue to violet color.
Tanzanite Prices are determined by the color and clarity of the gemstone. The more blue color are the most expensive type.
COLOR OF TANZANITE
The blue to violet colored gemstone is their most coveted property. It is rare to find a naturally blue stone in the rough, so most achieve their hue through heat treatments. The stone is heated to 500-600 degrees Celsius for about half an hour.
- Tanzanite - As the name suggests, the sole source for Tanzanite is Tanzania. More specifically in the Merelani Hills, situated in the Lelatema Mountains.
- Anyolite - Deep green crystals, colored by chromium and with Ruby crystals are found in Longido, Tanzania.
- Thulite - United States: California; Nevada; North Carolina; Washington. Canada; Greenland; Japan; Norway.
Tanzanite is 95% from Tanzania and all the gemstone in the market that are called Tanzanite are from Tanzania.
For more information please check the Tanzanite Foundation run by the Tanzanian Government for this rare gem.
It is safe to assume that all rich blue Tanzanite have been submitted to a stable heat treatment.
Tanzanite Stone (Blue Zoisite) hardness rages from 6 to 7 on the Mohs scale. However, it has a tendency to cleave and is rather brittle, which is not ideal for daily wear. Tanzanite are best used in occasional pieces or behind protective settings. They should be cleaned with a soft brush, mild detergent, and warm water.
STONE SIZES & COLLECTIBLES
- Rough Tanzanite gemstone have been found weighing hundreds of carats and reaches the largest size of all Zoisite in faceted gems.
- Smithsonian Institution (Washington, DC) houses a 122.7-carat blue Tanzanite and an 18.2-carat blue cat’s eye Tanzanite.
- A private collector owns a 220-carat Tanzanite.