Tanzanite is the transparent blue variety of the mineral zoisite. It was discovered as a new gem in 1967. Tanzanite was named by Tiffany & Co. after Tanzania, the country in which it was discovered. According to legend, tanzanite was discovered when a Masai tribesman found the sparkling stones in the remnants of a lightning fire, which had evidently heated the brown stones to a vivid blue. This led to the realization that heating zoisite--an opaque, usually brownish mineral--turns it beautifully transparent and blue. Tanzanite is one of the birthstones for December.