Largest white diamond ever, 'The Rock', to go up for auction on May 11

"The Rock," which was mined in South Africa, was once worn as a Cartier necklace by its former owner. The previous white diamond auction record was a 163.41 carat stone sold in 2017.

The biggest white diamond ever auctioned will go under the hammer this week in Geneva, as part of a Christie's sale that also includes two stones weighing more than 200 carats apiece.
 The auctioneer expects "The Rock," a 228.31 carat pear-shaped stone nearly the size of a golf ball, will fetch up to $30 million. A 555.55-carat black diamond thought to have originated from space is for sale. The world's biggest blue diamond sold at auction for $57.5 million.

"With these larger stones, they often lose some of the form to retain the weight," Max Fawcett, head of Christie's jewellery department in Geneva, told Reuters. He further said, "This is a wonderfully symmetrical pear-shaped form and... one of the most valuable stones ever sold at auction."

Sanctions against major producer Russia, as well as the resumption of VIP gatherings as pandemic restrictions ease, have boosted diamond prices.

"The Rock," which was mined in South Africa, was once worn as a Cartier necklace by its former owner. The previous white diamond auction record was a 163.41 carat stone sold in 2017. Christie's is also auctioning off a 205.07 carat yellow cushion-shaped stone dubbed "The Red Cross Diamond," with an undefined amount of the revenues going to the Geneva-based International Committee of the Red Cross (ICRC).

Christie's initially offered the Maltese cross faceted diamond in 1918 at a London auction where homeowners donated valuable household objects to support the war effort.