Monday, December 19, 2011

Tanzanite - Gemstone Of The 20th Century

Most gemstones have been known about for centuries, some for  millenia, so there is rich folk lore and tradition surrounding most of them.  The exception is Tanzanite, which was first discovered in 1967 near mount Kilimanjaro in Tanzania. It is the only place where the gemstone is found, and it is named after the country in Africa where it is found.

It was first marketed by Tiffany and Company in New York City.  It was first given the name blue zoisite as it is a variety of the mineral zoisite, but Tiffany changed it to Tanzanite because they thought it would help it sell better.  For ten years Tiffany had the exclusive rights to the stone, but in the 1970's the Tanzania government nationalized the mines.  Since the mines in Tanzania that produce the gem are nationalized, the government restricts the export of rough Tanzanite stones.  There are other entities that own parts of the mines and the supply of the gemstone is strictly controlled, thus the price has rose steadily over the years.

The color of Tanzanite can range from purple to blue. The rough stone is usually a reddish brown, and the rough stones are heat-treated to bring out the blue color. Almost all Tanzanite is heat treated at more than 900 degrees Farenheit and heat treatment has no affect on the value of the stone. The best quality stones range in color from ultramarine blue to sapphire blue with the most popular color being saturated blue which shows a purplish tint to it. It is a relatively soft stone,  and scratches more easily than many other gemstones. Care in wearing it and cleaning it is required.  In 2002 The American Gem Trade Association announced the Tanzanite has joined Turquoise and Blue Topaz as their birth stones for December.

Tanzanite has a rare property not found in most gems. When looked at in different light and at different angles it can appear to change color. From blue to violet to purple, some stones even show the colors dark red and gray. Tanzanite is usually clear with few inclusions. Stones with cracks or bubbles should be avoided as these could break.

Tanzanite is a beautiful stone, and considering it is found in only one 5-mile square place on earth, it is by its nature a rare gem that will only get rarer.  But it continues to be a popular stone, and has made its mark in the world of gemstones in a very short time.