I've always been a real fan of Tanzanite. As there are very few gems that display such a vibrant blue colour. But did you know that tanzanite is in actual fact blue zoisite. Tiffany's and Co. first started calling this gemstone Tanzanite, as they thought it would make it easier for them to market. They were absolutely right, Tanzanite is now the highest selling blue gemstone after Sapphire.
The first commercial deposits of Tanzanite were discovered as recently as 1960, in the foothills of Mount Kilimanjaro, Tanzania. Deposits were found over a minute 8 kilometre area. It's meteoric rise to success sees these deposits depleting rapidly, hence the exponential rise in price in recent years.
Small traces of vanadium within the mineral structure are what gives Tanzanite it's blue colour. The pleochroic nature of Tanzanite means that it's colour can change depending on which angle it is viewed from. Some specimens can appear to be blue from one angle, and violet to red from another.