There are three birthstones for the month of December: tanzanite, zircon and turquoise. All three of these stones are a deep blue colour and have their own history and chemical composition. One of the more interesting of the three is tanzanite, a gem you may not have heard of before. This rare gem is only found in Tanzania and was only recently discovered in 1967. Tanzanite gets its deep blue colour from trace amounts of vanadium. Discover Tanzanite, Zircon and Turquoise Jewellery by the world's most exciting designers.