Penn Diamond Exchange Blog

The rare blue diamond that we previously blogged about has been sold. It was put up for sale by London-listed Petra Diamonds, which extracted it last year from the historic Cullinan mine in South Africa, the world's most regular supplier of blue diamonds of size and quality. Blue are the rarest of the diamond family after reds.

The final price includes a commission paid by the buyer to the auction house. The stone sets a record price per carat for any gemstone sold at auction of $1,349,752 per carat, (890, 275 pounds) Sotheby's said.

The owner will have bragging rights, as well as the right to name the stone, which is mounted in a platinum ring.