HONG KONG — An exceptionally rare 102.39-carat diamond may become one of the most expensive stones ever to sell at auction when it goes under the hammer in Hong Kong on Oct. 5.
Although auction house Sotheby's declined to provide a pre-sale estimate, diamonds of similar size and quality have previously attracted bids between $12 million and more than $30 million.
Cut from a 271-carat rough diamond discovered in Ontario, Canada, in 2018, the oval stone has achieved top rankings in each of the "four Cs" — cut, color, clarity and carat weight — by which a diamond is judged, the auction house said.
It has been classified as "D color," the highest grading for a white diamond, and is considered to be internally and externally "flawless," placing it among the world's most chemically pure, transparent and symmetrical diamonds. It also belongs to a rare subgroup of diamonds that contain little to no nitrogen.
Only seven D color flawless (or internally flawless) diamonds weighing over 100 carats have ever appeared at auction before, according to Sotheby's.
Of these, the most expensive was a rectangular 163.41-carat diamond, which sold for $33.7 million at Christie's in Geneva, while the most paid for an oval variety stands at $30.8 million in 2013. If the diamond going under the hammer in Hong Kong next month attracts the same per-carat price as this latter sale, it would sell for more than $26 million.
'Transformative' time for auction market
The rare oval diamond is being offered without a reserve, meaning that it will be sold regardless of the size of the highest bid. Bidding will open online from September 15, with the sale concluding at a live auction in Hong Kong on October 5.
In the meantime, the item is set to go on display at appointment-only previews in Beijing, Shanghai, New York and Taipei.
Patti Wong, chair of Sotheby's Asia, expressed confidence about the sale, despite the challenges presented by the COVID-19 pandemic, in what she called "deeply transformative months for the auction market."
While white diamonds can attract huge bids at auction, pink and blue varieties have achieved even larger sums in recent years. In 2017, a 59.60-carat pink diamond known as the Pink Star became the most expensive jewel ever to sell at auction when it went for $71.2 million at Sotheby's in Hong Kong.
Two years earlier, the 12.03-carat "Blue Moon" diamond sold for $48.4 million, also through Sotheby's.
Photos: Diamonds up for auction
Take a look at photos of diamonds up for auction over the years.
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Auction house Sotheby's declined to provide a pre-sale estimate of a rare 102.39-carat diamond, but diamonds of similar size and quality have previously attracted bids between $12 million and more than $30 million.
Jewelry specialist Joanna Gong displays a rare 100-plus-carat oval diamond Wednesday at Sotheby's in New York. The diamond cut and polished from a 271-carat rough discovered in 2018 at the Victor mine in Ontario, Canada, will be auctioned in Hong Kong on Oct. 5, 2020.