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However, most tanzanite is subjected to artificial heat treatment to improve its
color: this significantly subdues its However, most tanzanite is subjected to artificial
heat treatment to improve its color: this significantly subdues its trichroism.
Maasai tribesmen discovered Tanzanite in 1967, supposedly after lightning struck
and caused a bush fire which heated the raw brown zoisite into the vivid
blue-purple. Whether this is true or not is debatable.
The name tanzanite was a trade name coined by Tiffany & Co. shortly after the gem's
discovery, an obvious allusion to its country of origin. This was thought necessary in
order to make the stone marketable to the public: the name has since stuck as a
varietal designation. Tanzanite's present-day popularity as a gemstone is largely
thanks to Tiffany's marketing campaigns. The mining of tanzanite nets the
Tanzanian government approximately USD $20 million annually, the finished gems
later being sold mostly on the US market for sales totaling approximately USD $500
million annually.
In June of 2003, the Tanzanian government introduced legislation banning the
export of unprocessed tanzanite to India (like many gemstones, most tanzanite is cut
in Jaipur). The ban has been rationalized as an attempt to spur development of local
processing facilities, thereby boosting the economy and recouping profits. This ban
was phased in over the next two years, until which time only stones over 0.5 grams
were affected.
This is a serious situation for the city of Jaipur, as one-third of its annual gem exports
are of tanzanite. Some members of the industry fear the ban will set a precedent,
leading Tanzania to ban the export of all raw gem material, including the country's
production of tsavorite, diamond and ruby.
In April 2005, a company called TanzaniteOne Ltd. publicly announced that they
had taken control of the tanzanite mine known as "C-Block". Over the next year, this
company established a De Beers-like control over the tanzanite market. This is the
first time that a colored gemstone has been controlled in this way. In August
2005, the largest tanzanite crystal was found in the C-Block mine. The crystal
weighs 16,839 carats (3.4 kg) and measures 22 cm by 8 cm by 7 cm.
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