Tanzanite
Tanzanite takes its common name from Tanzania, the East African nation that is the only place in the world it is found. More formally, it is known as blue zoisite.
First discovered in 1967, this gemstone is a gorgeous blue with purple highlights. Soon after that, some tanzanite jewellery went on sale at Tiffany's and proved very popular.
According to the International Coloured Gemstone Association, this stone is especially valued because it comes from only one source.