Rare Blue Diamond Fetches Record Price

This rare blue diamond, set in a Trombino ring by Bulgari, brought in almost $9.6 million. (Photo: Bonhams)A beautiful, rare blue diamond weighing 5.30 carats fetched more than five times its estimated price at auction on Wednesday, bringing in nearly $9.6 million and setting a new price-per-carat record.

PHOTOS: The Most Memorable Diamonds in Movies

"We are delighted with the price it has made," Jean Ghika, director of Bonhams Fine Jewelry, which held the sale in London, said in a statement. "It was a sensational stone which charmed everyone who viewed it prior to the sale."

Also on Shine: Actress Brittany Murphy's Clothes Go Up For Auction

The 5.30-carat diamond -- a little smaller than the diameter of a dime -- was made into a "Trombino" ring by famed Italian jewelry designer Bulgari in 1965. It's a cushion-shaped fancy deep-blue diamond, set horizontally and framed by brilliant-cut and baguette-cut white diamonds. (In gemstone terms, "fancy" means that the color is very intense.) The winning bid came from Graff Diamonds, an international jewelry house on Bond Street in London, Bonhams reported.

The gem gets its unique color from natural traces of the element boron mixing with the carbon atoms in the stone. Since boron conducts some electricity, blue diamonds look even more blue when they are warm. Less than one percent of all diamonds mined are blue.

"Blue diamonds, especially those over 5.00 carats, are extremely rare to see on the market and continue to be highly sought-after," Ghika said. "We are honored to have handled the sale of such a unique gem."

People in the packed salesroom competed for the rare gem while collectors and experts called in their bids on the auction house's 25 phone lines. The ring was expected to go for about $1.6 million; instead it went for close to $9.6 million, or $1.8 million per carat. The old record was $1.68 per carat.

While rare and gorgeous, this isn't the biggest or most-famous blue diamond out there. That honor belongs to the 45.52-carat Hope Diamond, a deep blue jewel that was purchased by King Louis XIV of France in 1668. It was stolen during the French Revolution, and reappeared in London in 1812; an American heiress, Mrs. Evalyn Walsh McLean, bought it and had it made into a necklace, accenting it with 16 white diamonds and hanging it on a chain set with 45 more white diamonds. It is currently on display at the Smithsonian Institution's Museum of Natural History in Washington, D.C.

Also on Shine:

$5.7 Million Dress Dazzles with Black Diamonds
Is This The World's Most-Expensive Diamond Dress?
Costco Selling $1 Million Diamond Ring