Wittlsbach-Graff Diamond. Originated in India, this diamond is fancy deep blue and weighs 31.06 carats. This diamond has important historical significance as it was owned by Philip IV of Spain and came into the hands of many other European emperors. However, it dropped in value due to the fact that it was altered, thus compromising its historical integrity. It is currently in the possession of Hamad bin Chalifa Al Thani and is estimated to be around $80 million.