The Pink Star, one of the World's Great Natural Treasures - Formerly known as the Steinmetz Pink, is a 59.60-carat pink diamond. According to Sotheby's, the Pink Star is the most valuable diamond ever to be offered at auction & the largest internally-flawless, fancy-vivid pink diamond that the Gemological Institute of America (GIA) has ever graded. The diamond is exceptional for its size, color grade, & type. [November 13, 2013 in Geneva, Sotheby's auctioned the The Pink Star for 83 million…