The largest white diamond ever to come to auction will hit the block at Christie’s in Geneva on May 11. The 228 ct, pear-shaped diamond carries a presale estimate of $20-million to $30-million (~R434-million). The stone, which is about the size of a chicken’s egg, was mined about 20 years ago in South Africa but is only now coming up for public sale.

"Right now there is a great appetite in the market for diamonds," says Rahul Kadakia, the international head of jewellery at Christie’s. The firm also brokered the gem’s initial private sale to a collector, who held on to it for most of the past two decades. "With the market the way it is — in 2021 there was a huge resurgence both in the art market and the jewellery market—the second owner approached us and said, 'How would you feel about marketing this for us at public auction?'" 

Unsurprisingly, Kadakia felt just fine with an assignment to sell a record-breaking gem. "It’s a once-in-a-lifetime opportunity," he says. "If, after the sale, you come up to me and say, 'Can you find me another 230-ct diamond?' — well, I can’t."

INVESTMENT POTENTIAL
Should the stone sell for its high estimate, it would immediately become one of the most expensive white diamonds in the world. Yet Kadakia says the estimate’s comparatively modest price per ct — just shy of $88 000 (R1.3-million) — makes the gem an attractive investment. "It’s quite appealing to collectors from all areas of the market," he says, "ranging from pure investors who just want to buy a big portable asset and put it away to someone who wants to buy it to enjoy it as a set piece of jewelry and, at the same time, put their money into something quite portable."

Christie’s is eager to compare the stone’s estimate to white diamonds it’s sold previously, including a 102-ct stone that sold in 2013 for $26.7-million and an emerald and diamond de Grisogono necklace featuring a 163-ct centrepiece, which sold for $33.7-million in 2017. The former diamond’s price per ct was around $262 000; the latter’s was about $206 000. 

Both of those diamonds were designated as "D" colour, meaning they were truly colourless; this 228-ct diamond, in contrast, is graded G, meaning that it is "near colourless", three steps below on the Gemological Institute of America’s colour scale. 

Kadakia acknowledges that this grade impacts the price, but says it should do nothing to alter its desirability. "So, with diamonds it’s the four Cs: cut, colour, clarity, and carat weight," he says. "And that determines the price for three-, five-, 10-, 50-ct stones, maybe even the 163-ct stone which we sold in 2017."

But here, he argues, "you have a stone which weighs almost 230 cts. Is there really a price per ct, or are you looking differently at it, like a work of art?" He urges people to hold the stone in the palm of their hand. "It feels like $100-million."

'NOTHING IS IMPOSSIBLE'
Diamond prices have risen precipitously in recent months. De Beers yanked prices up by nearly 10% at its sale in January, with cheaper diamonds jumping as much as 20%.

Kadakia anticipates strong interest from the Middle East and is accordingly commencing the diamond’s world tour in Dubai. After that, the stone will visit Taipei and New York, and then it goes to Switzerland for auction.

Should buyers decide that this is something they’d like to wear in public, "a necklace would be the most logical vehicle" for the stone, Kadakia says. "This is not going on a ring, I can tell you that much."

Although, he adds on reflection, "I have seen clients wear rings up to 100 cts, so nothing is impossible in our world."