When the Lesotho Promise diamond was mined in late 2006, at 603 carats it was the 15th largest rough diamond ever discovered. It was also graded D, the highest color rating a diamond can receive. Needless to say, when it went up for auction there were quite a few interested parties, none more so than the famed jeweler Graff, which bid $12.4 million to win it. Graff set 35 people to the months-long task of analyzing the diamond and deciphering the most fruitful way to cut it. Rather than split up the resulting bounty, Graff opted to use all 26 flawless diamonds, totaling 223.35 carats, in one spectacular Lesotho Promise necklace.