Sotheby’s is presenting the largest blue diamond ever seen at auction during their October 7 jewelry auction in Hong Kong. The Premier Blue is a rare 7.59-carat, internally flawless fancy vivid blue diamond, estimated to fetch $19 million. It’s the largest round fancy vivid blue diamond ever graded, a cut rarely seen in colored diamonds due to the high wastage involved. See, it’s not ALWAYS about size. (Photo: Sotheby’s)