De Beers to Start Third-Party Polished SalesRAPAPORT... De Beers first auction of other companies exceptional polished diamonds will feature close to 50 stones, one of which weighs nearly 21 carats, the company said Tuesday. All diamonds on offer at the inaugural sale on June 29 either exceed 2.50 carats or have a fancy color, and have been confirmed by De Beers grading laboratory the International Institute of Diamond Grading and Research (IIDGR) as natural and untreated. In addition to the cushion-cut, 20.64-carat, fancy light yellow, 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 fancy yellow, VS1-clarity diamond weighing 5.53 carats. All sellers must register in advance and comply with De Beers auction-trading standards for diamond provenance and for seller and product integrity, the miner said. The pilot sale will take place on De Beers online auction platform, enabling buyers and sellers to do business anonymously. The event will occur on the same day as De Beers first sale of polished diamonds manufactured directly from its own rough, so buyers can conveniently source polished from both sales.