The 507-carat diamond recently put up for sale by Petra Diamonds, sold for $35.3 million, breaking the record for the highest price paid for a rough diamond. The diamond was bought by Hong Kong-based private jewelry retailer Chow Tai Food Jewelry Co. Ltd., reports say. At the time the stone was discovered at Petra Diamonds’ Cullinan Mine in South Africa, it was valued by analysts to be worth around $20 million, and the company expected a sale price of around $25 million riding on rising rough diamond prices and higher buyer interest. %% The 100 gram-stone was estimated as among the world's top 20 high-quality rough diamonds.