Taaffeite is a beautiful and rare gem mineral. It is one of those odd minerals that was first discovered from already cut and misidentified gemstone specimens. The gems were thought to be mauve spinels. But the discoverer and subsequent lender of his name, Count Taaffe realized that these "spinels" were doubly refractive. Something that is impossible with the isometric spinel. Taaffeite has properties that are very similar to spinel such as hardness, density and index of refraction and is therefore difficult to distinguish from the much more common gemstone spinel. Its the double refraction that is the key and the only way that most of the gem quality taaffeite has been found among the other gemmy grains found in alluvial deposits in Sri Lanka. Some lower grade taaffeite has been found in China associated with fluorite. But an original source for the taaffeite grains has yet to be discovered!