South Africa 's De Beers Consolidated Mines , which controls 80 % of the world diamond market through its London - based diamond Selling Organization , is raising its diamond prices an average 10 % . Rough diamonds were already trading at a premium over De Beers ' own quotes on the open market , especially in the Far East . In Japan , the second biggest diamond - jewelry market after the US , appreciation of the yen reduced diamonds ' cost . Per - diamond prices of D - flawless diamonds have risen to $ 200 from $ 12,000 since the beginning of the year . diamond Beers saved diamond trade from an early-80s recession through an aggressive marketing campaign and withholding stocks .
South Africa's De Beers Consolidated Mines, which controls 80% of the world diamond market through its London-based Central Selling Organization, is raising its diamond prices an average 10%. Rough diamonds were already trading at a premium over De Beers' own quotes on the open market, especially in the Far East. In Japan, the second biggest diamond-jewelry market after the US, appreciation of the yen reduced diamonds' cost. Per-carat prices of D-flawless diamonds have risen to $14,800 from $12,000 since the beginning of the year. De Beers revived diamond trade from an early-80s slump through an aggressive marketing campaign and withholding stocks.