Tanzanite is the purple, violet, and blue variety of zoisite. It was first brought to market by Tiffany & Co. in the mid- to late 1960’s. The only commercial source of the stone is Tanzania and is considered a National Treasure by the Tanzanian government. The future of tanzanite is unclear since the world’s production only comes from an area that is barely 6 kilometers long and 2 kilometers wide. Tanzanite became so popular by 2002 that it was added to the list of alternative December birthstones. The most valuable stones are an intense, rich blue with high clarity. Tanzanite is strongly pleochroic and as the stone is rotated you can see blue, reddish purple, and bluish green or greenish yellow colors.
- Optical Properties
- Characteristic Physical Properties
- Chemistry & Crystallography
A large tanzanite of fine deep color provided this unpolarized spectrum . The main feature is the intense broad absorption band from 560nm to 630nm. Moderate band is also seen centered at 520nm. and a weak narrow line at 450nm. Very little variation was seen between the blue and violet rays other than a weaker absorption in the blue ray.
Color due to vanadium. An untreated tanzanite retains its trichroism with a greenish overtone in the body color. A moderate absorption is seen from 540nm. to 590nm. with no transmission below 440nm. nor above 680nm. A weak narrow absorption line can be seen at 440nm.
We acknowledge the significant scientific contributions of John S Harris, FGA to the study of gemstone spectra and with deep appreciation to him, acknowledges the use of his images and related notes about gemstones and their spectra in the educational materials on this website.
Countries of Origin
Tanzania, United Republic Of; Unknown
Tanzanite is a lush, opulent bluish-violet... or it's a vibrant violet-blue... or it's a regal violet-purple. This stunning stone is pleochroic - a fancy gemstone word that means it reflects different colors when viewed at different angles. This allows cutters to fashion gems with a range of color in a single piece. Tanzanite is a zoisite and somewhat brittle. It's a 6 ½ on the Mohs hardness scale. It's a wearable stone you can enjoy for many years to come. Within one year of its discovery tanzanite had set the gem world spinning. In 2002, it was named an alternative birthstone for December.
Normal, gentle handling and avoid extreme temperature changes. Gentle wear, avoid ultrasonics and high heat in CVD coated stones.
More About Tanzanite
Among the Masai tribesman it is said that a magical fire, lit from the heavens, swept through the area at the base of Mount Kilimanjaro. What made the fire magical? It had the power to transform the brown rocks found on the ground into brightly colored purple-blue stones. When the dust cleared away, and the blue stones were found, it was agreed that the fire brought good fortune to the people. Why do we love tanzanite? It's a spectacular blue, pleochroic, and found in only one place in the world. Oh... and it's many times rarer than diamonds. Wow.