RAPAPORT... Sotheby’s will sell a group of eight fancy-blue diamonds from De Beers across its global Magnificent Jewels auctions, expecting the set to bring in more than $70 million.The stones are cut in various shapes and range from 1.22 to 11.29 carats, with a total weight of 32.09 carats, Sotheby’s said last week. The polished originates from five rough blues that De Beers and Switzerland-based...