14kt yellow gold 18" Vintage trillian tanzanite & 0.10ct diamond ribbon "arrow" pendant. Tanzanite is an extraordinarily rare blue-violet gemstone that belongs to the zoisite mineral family. First discovered in 1967, it exhibits flashes of royal blue & vibrant violet. It was famously branded as "tanzanite" and introduced to the global luxury market by Tiffany & Co. in 1968. Tanzanite still is sourced only in Kenya, Africa, and it serves as one of the December birthstones.