RAPAPORT... De Beers' first auction of other companies' "exceptional"polished diamonds will feature close to 50 stones, one of which weighs nearly21 carats, the company said Tuesday. All diamonds on offer at the inaugural sale onJune 29 either exceed 2.50 carats or have a fancy color, and have been confirmedby De Beers' grading laboratory - the International Institute of DiamondGrading and Research (IIDGR) - as natural and untreated. In addition to the cushion-cut, 20.64-carat, fancy lightyellow, VS2-clarity diamond, goods will include a pear-shaped, 7.21-carat,D-color, flawless one, and two more cushion-cut diamonds - one a 1.57-carat,fancy vivid yellow, internally flawless stone, and the other a fancyyellow, VS1-clarity diamond weighing 5.53 carats.All sellers must register in advance and comply with DeBeers' auction-trading standards for diamond provenance and for seller and productintegrity, the miner said. The pilot sale will take place on De Beers' online auctionplatform, enabling buyers and sellers to do business anonymously. The eventwill occur on the same day as De Beers' first sale of polished diamondsmanufactured directly from its own rough, so buyers can conveniently sourcepolished from both sales.