Tanzanite was first discovered in 1967, when discovered people thought it was originally a new sapphire deposit. However, tanzanite has a more violet purple hue than sapphires and is actually part of the zoisite family. Tanzanite is the birthstone for those who are born in December. This beautiful stone is thought to be an heirloom gemstone as it can only be found in one location in the world. This makes tanzanite even more rare than a diamond.