RECORDS When Sotheby’s sold a 12.03 ct. fancy vivid blue last November, it was dubbed the Blue Moon because it seemed like the kind of diamond that came around—well, you know. Now, seven months later, Christie’s Geneva is selling a gem in the same rarefied ballpark. On May 18 it will auction the Oppenheimer Blue (pictured above), which at 14.62 cts. stands as the largest fancy vivid blue ever offered at auction. Named for its onetime owner, former De Beers honcho Sir Philip Oppenheimer, the VS1 emerald cut is expected to fetch between $38 million and $45 million. Its provenance might help. “Sir Philip could have had any diamond he wanted,” says François Curiel, chairman of Christie’s Asia Pacific and China, “but he chose this one.” SHOWS Visitors to Baselworld may have been surprised to find themselves far from the madding crowd. Known for its bustling hallway