Why the market for 100-carat diamonds is booming

Sotheby's is set to auction a 102-carat diamond with no reserve, but competition is likely to be fierce

Sotheby's is auctioning a 102-carat D-Flawless diamond with no reserve
Sotheby's is auctioning a 102-carat D-Flawless diamond with no reserve

‘Revenge buying’ was the term given to the pent-up demand for luxury products that saw queues forming outside Harrods, Hermès and Dior the day the shops reopened in June. But no designer handbag splurge can compare to the ultimate revenge buy: a diamond the size of a Creme Egg worth £4.8 million.

That was the latest stone to enter the custody of Moussaieff, the family-run jewellery house headed by the revered Alisa Moussaieff, who has been called the ‘matriarch of the diamond industry’. No stranger to extraordinary gems, over the decades the house has become known as a specialist in coloured diamonds and rare stones - and its newest purchase is entirely unique.

The 100.85-carat unmounted stone was auctioned at Christie’s Magnificent Jewels sale in Geneva in July. It fetched CHF 5.6 million (approximately £4.8 million), significantly more than its high estimate of CHF 4.5 million. Described simply as ‘property of a lady’, the diamond is D-colour - the highest possible rating - Internally Flawless and certified Type IIa, meaning it is chemically pure. Less than two percent of all gem-quality diamonds are Type IIa. 

The 100ct D-colour shield-cut diamond purchased by Moussaieff

Unusually, it is cut into a shield shape. Most diamonds of this size are polished into round or pear-cuts to maximise their brilliance, but this stone has a distinctively angular silhouette. It calls to mind another Moussaieff stone: the 5.11ct Moussaieff Red, the world’s largest Fancy red diamond (the rarest colour of all). Also cut and polished into a shield shape, the stone was purchased in 2001 by Alisa’s late husband Shlomo Moussaieff.

“In spite of these challenging times, we are extremely satisfied with our acquisition and are certain that there is and always will be a demand for that special item at the right price and with such a strong visual impact,” said Mrs Moussaieff in a statement.

The house has also welcomed another diamond in the form of newly appointed CEO David Warren, the former international director of Christie’s Jewellery, who joined the house last month. In a twist of fate, the Geneva sale at which Moussaieff bought the 100ct stone was one of the last of Warren’s 42-year career at the auction house.

He describes the stone as a “gem of gems” with an “elegant and unique shape”. Mrs Moussaieff is now considering how best to set the diamond to highlight its unique beauty. “It will become the focal point of an extraordinary art jewel, appealing to both collectors of rare gems and leaders of style,” says Warren.

The 102-carat D-Flawless diamond to be auctioned by Sotheby's on October 5

For anyone wishing to add to their own collection, there is another chance to own a stonking stone as Sotheby’s prepares to auction a 102.39ct oval diamond at a single-lot auction in Hong Kong on October 5. In a world first, the diamond will be offered with no reserve, meaning that it will sell to the highest bidder with no predetermined price.

The diamond is another D-colour Type IIa stone, rated Flawless - the highest possible clarity rating, meaning it has no internal or external inclusions or blemishes. It was cut and polished from a 271ct rough discovered in Ontario, Canada in 2018.

Gary Schuler, Sotheby’s worldwide Chairman of Jewellery, describes the diamond as “the best of the best...it is difficult to overstate its rarity and beauty”. It is the second-largest oval diamond of this quality to appear at auction, and only the eighth 100-carat-plus D-colour Flawless or Internally Flawless diamond ever to be auctioned. 

The current world record for the world's most expensive D-Flawless diamond belongs to the 163.41-carat emerald-cut stone set in the Art of de Grisogono - Beyond Jewellery, Creation 1 necklace, which sold for $33.7 million at Christie’s Geneva in 2017. The Sotheby’s sale is the first time that a stone of this quality has been offered without reserve.

However, it’s unlikely that the winning bidder will grab themselves a bargain. As Patti Wong, Chairman of Sotheby’s Asia, comments, “demand has shown tremendous resilience during the first part of the year and we feel it is now time to let the market speak. Diamonds of this calibre attract interest well beyond the traditional pool of collectors.”

Lisa Levinson, UK head of marketing and communications at the Natural Diamond Council, believes that in times of uncertainty, mammoth diamonds are more attractive to those with the means to buy them than ever.

The current record for the world's most expensive D-Flawless diamond belongs to the 163.41-carat emerald-cut stone featured in this De Grisogono necklace, which sold for $33.7 million

“Diamonds over 100 carats are considered the world’s rarest and most desired objects,” she says. “Their allure has remained constant throughout history, for those wanting to invest in and possess something that is exceptionally unique and unlikely to ever lose its value. These diamonds are one-in-a-billion; they don’t come around often.

“Despite turbulent times, these stones never lose their appeal and intrinsic value,” she continues. “The rarer the diamond, the more it will appreciate over time. Discerning buyers see them as an investment, as well as miracles of nature that have a strong emotional value.”

The last diamond of a similar quality, a 118.28ct oval diamond, sold at Sotheby’s Hong Kong in 2013 for $30.8 million - and the house also privately sold a 102.34-carat, D-Flawless, Type IIa round brilliant diamond in April 2018 for an undisclosed sum. The house said only that the price per carat ‘far exceeded any colourless diamond sold at auction’. The current auction record is $260,252 per carat.

While the buyer of that particular stone paid a premium for their privacy, all eyes will be on this unprecedented auction, which will undoubtedly act as a litmus test of the market for extraordinary diamonds over the months and years to come.

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