Take a look at the largest white diamond ever put up for auction

The biggest white diamond ever to be sold at auction, dubbed “The Rock”, will go under the hammer in Geneva on Wednesday 11 May and is predicted to fetch $20-30 million (€18-38 million).

The 228.31-carat stone is up for grabs alongside a historic intense yellow diamond associated for more than a century with the Red Cross, which will receive some of the profits from its sale.

Could ‘The Rock’ become the most expensive white diamond ever sold?

‘The Rock’ will be offered in Geneva during a ‘Christie’s Magnificent Jewels’ saleFabrice Coffrini/AFP

The Rock is ‘a truly exceptional pear-shaped diamond”, said Max Fawcett, head of the jewels department at Christie’s auction house in Geneva.

It is “the largest white diamond ever to be offered at auction”, he told AFP at a preview.

The Rock is currently in the hands of an unnamed owner from North America.

As well as being the largest diamond ever auctioned, it could also break sales records when it goes under the hammer.

“It’s perfectly symmetrical … I expect there be fireworks on Wednesday,” Fawcett said.

The expert said that there were only a handful of diamonds of similar size and quality to The Rock. The Christie’s record for a similar white diamond is $33.7 million, fetched in Geneva in 2017 for a 163.41-carat gem.

Larger than a golf ball, The Rock was extracted from a mine in South Africa in the early 2000s. It has been shown in Dubai, Taipei and New York ahead of the sale in Geneva.

Red Cross gem

Picture shows ‘The Red Cross Diamond’, a 205,07 carats yellow, cushion-shaped diamondFabrice Coffrini/AFP

Bidders will also be vying for The Red Cross Diamond, a cushion-shaped, 205.07-carat canary yellow jewel, which has a price estimate of seven to 10 million Swiss francs (€6.7-9.5 million).

“I expect that it will achieve much more on the day of sale,” said Fawcett.

A large chunk of the proceeds will be donated to the International Committee of the Red Cross, which is headquartered in Geneva.

The original rough stone was found in 1901 in a De Beers company mine in South Africa and is said to have weighed around 375 carats.

As well as ranking among the largest diamonds in the world, a striking feature is its pavilion, which naturally bears the shape of a Maltese cross.

The stone was first put up for sale on April 10, 1918 at Christie’s in London. It was offered by the Diamond Syndicate in aid of the British Red Cross Society and the Order of St John.

The Red Cross Diamond fetched £10,000, approximately £600,000 (€700,000) in today’s money. It was bought by the London jewellers S.J. Phillips.

It was sold again by Christie’s in Geneva in 1973, fetching 1.8 million Swiss francs, and is now being offered by the auction house for a third time.

“For nearly half a century, our family has had the privilege of safeguarding The Red Cross Diamond,” the gem’s anonymous private owner said in a statement.

Check out the video above for a closer look at the diamonds going on sale in Geneva