'Oppenheimer Blue' Could Challenge 'Blue Moon' For The Title Of Priciest Diamond Ever; Record Now Stands At $48.5m

In November 2015, the 12.03-carat "Blue Moon" set an auction record for the priciest diamond ever when the fancy vivid blue gem sold for $48.5 million at Sotheby's Geneva. But on May 18, the 14.62-carat "Oppenheimer Blue" has a chance to dethrone the Blue Moon when it goes under the hammer at Christie’s Magnificent Jewels sale in Geneva.

Oppenheimer Blue, which carries a pre-sale estimate of $38 million to $45 million, is the largest fancy vivid blue diamond ever offered at auction. Some experts believe Christie's high estimate is on the conservative side, giving the stone a viable chance of setting a new record.

Despite both diamonds being of similar color, the cushion-shaped Blue Moon (now called the Blue Moon of Josephine) was rated internally flawless, while the rectangular-cut Oppenheimer Blue sits one grade below at VVS1 clarity.

Even if the Oppenheimer Blue doesn't match Blue Moon's record per-carat selling price of $4.03 million, it could still sell for more because it is 2.59 carats larger.

"The Oppenheimer Blue was named in honor of a very special connoisseur — its previous owner, Sir Philip Oppenheimer," noted Rahul Kadakia, Christie's International Head of Jewelry. "The Oppenheimers have been leaders in the diamond industry for generations and Sir Philip could have had any diamond he wanted. But he chose this one, with its perfect hue, impeccable proportions and fabulous rectangular shape."

Kadakia called the "Oppenheimer Blue" the "gem of gems," and "one of the rarest gems in the world."

In a promotional video, the narrator described the rise in the popularity of blue diamonds.

"Blue diamonds have gained a wider following," he said, "not only because they are stunning, but because there are so few of them available in the world."

The magnificent gem will be offered for sale in its original platinum mounting by Verdura. The large blue center stone is flanked by two trapeze-shaped white diamonds.

Fancy vivid blue diamonds are extraordinarily rare. A Gemological Institute of America study of 462 blue diamonds revealed that only 1% attained the color grade of "fancy vivid."

Christie’s Magnificent Jewels sale is scheduled to take place at the Four Seasons Hotel des Bergues on May 18.