Today’s topic starts with the letter “T”.
“T” is the letter for today and the stone is Tanzanite, a pretty blue-purple color. It was discovered in Tanzania in 1967 and was named after the location. It is usually as reddish brown in its rough state and is heat treated to enhance the color.
The deep blue color stones are harder to find now. The paler colored stones are easier to find and are faceted and used for beads.
In 2002, the American Gem Trade Association chose Tanzanite as the December birthstone, the first change to the birthstone list since 1912.
The largest cut stone is 252.2 carats and is recognized by the Guinness World Records and the largest rough cut is 16,839 carats (7.46 lbs.) discovered in 2005.
It was estimated that two million carats of tanzanite were mined between 1967 and 1971 when the mines were nationalized by the government. In 1990, the government divided the mines into four sectors (A, B, C, and D) and leased two sectors (A and C) to large companies and the remaining sectors were reserved for the local miners. In 2005, the lease for sector C for was renewed for 40 million dollars.
In 2003, legislation was introduced to prohibit the export of rough cut stones to India (where many gemstones were processed) in order to spur development of local processing businesses. This was phased in over two years when only stones over .5 grams were affected. That was changed in 2010 to stones over 1 gram.
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