An individual from the zoisite group of minerals, tanzanite is discovered just in shades of blue or purple, the most famous being a violet-blue. While tanzanite is normally treated with heat to improve its blue shading, it is normally trichroic, implying that it shows three unique hues (blue, purple and bronze) when seen from various angles. The mohs scale rates it at 6.7-7 in terms of its hardness. It gets its name from the nation of Tanzania, the only place on the planet where it is found. Tanzanite was found quite recently in 1967, and was called by gemstone specialists as the "the gemstone of the twentieth century." Owing to its quickly developing prominence, In 2002 the American Gem Trade Association included it as an alternative December birthstone in the US.