World's largest's white diamond expected to fetch $30 million

The largest white diamond ever, the Rock, is set to be auctioned again next week in Geneva. The pear-shaped stone is roughly the size of a golf ball, and it is 228.31 carat. Its former owner wore it as a Cartier necklace.

The Rock was mined in South Africa.

Auctioneers are expecting the stone to sell for up to $30 million, reported Reuters. Diamond prices are increasing due to sanctions on major producer Russia as well as the return of VIP events as pandemic restrictions are being removed.

About the shape of the rare diamond, Max Fawcett, the head of Christie's jewellery department in Geneva, said the Rock has a perfectly symmetrical pear-shaped form which makes it one of the rarest gems ever to be sold at an auction. He added that large stones often have to sacrifice some of their shapes in order to keep their weight.

The Rock will be part of a sale by Christie's which features another stone weighing over 200 carats. The previous auction record held by a white diamond was a 163.41-carat gem sold in 2017.

The upcoming auction will see the sale of another large stone, a 205.07-carat yellow, cushion-shaped stone named "The Red Cross Diamond". It has a Maltese cross faceted at its base. A portion of the proceedings will go to the Geneva-based International Committee of the Red Cross (ICRC).

It was first sold by Christie's in 1918 at a London auction where people were selling precious household items to help the war. It fetched 10,000 (now $12,350) at the time and helped the British Red Cross Society. A Red Cross spokesperson said the proceeds from next week's auction will be used to bring clean water to people affected by conflict.