Mellon estate's pear-shaped diamond sets auction record for any blue diamond

A Fancy Vivid Blue pear-shaped diamond from the estate of Rachel "Bunny" Mellon has sold for $32.6 million. It's an auction record for any blue diamond.

Sotheby's says seven people bid on the 9.75-carat gem Thursday before it sold to an anonymous Hong Kong collector.

The diamond is mounted in platinum. It carried a $10 million to $15 million pre-sale estimate.

The Wittelsbach Diamond held the previous auction record for any blue diamond. It sold at Christie's for $24.3 million in 2008.

Mellon died in March at 103. She was the widow of philanthropist Paul Mellon and heir to the Listerine fortune.

Sotheby's also has been selling paintings and other objects from Mellon's homes this month.