Sphene, also known as Titanite, is a gemstone often found in Madagascar and Pakistan.  It has a supremely high dispersion (significantly higher than that of Diamond), which works brilliantly with its myriad of colours, which range from a vivid Green, to a Golden Yellow, to a rich Cognac.  Whilst Sphene is a relatively soft gemstone and unsuited for use in rings, its sheer fire and colour makes it a fantastic option for use in earrings or pendants.