What's the Golconda Blue Really Worth?
April 17, 25
Size doesn't necessarily matter. The Golconda Blue, at 23.24 carats, is the largest fancy vivid blue diamond ever to be offered at auction.
But that doesn't mean it will automatically fetch the highest price.
The estimate by Christie's Geneva is $35m to $50m and anyone ready to splash that kind of cash will be looking beyond the 4Cs for expert analysis of the intensity, hue, and purity of its color.
Those are the critical - and measurable - factors that determine price. As well as who wants it, and how badly, on the day. Those are factors that are far more difficult to measure.
"In ultra-high-value colored diamonds, price is a function of multiple interdependent factors," says Lina Kurganoff, head of client and business relations at the Fancy Color Research Foundation (FCRF).
"At first glance, one might think bigger equals better, but in the world of ultra-rare colored diamonds, carat weight is just one part of a much more complex equation," she tells IDEX Online.
To underscore just how rare the Golconda Blue is, she provides some statistical context from the FCRF database.
"Only about 0.6 per cent of all fancy color diamonds are blue. Just 0.0001 per cent of those blue diamonds fall into the 20-24 carat weight category. And only 8.6 per cent of blue diamonds are graded as Fancy Vivid."
Color is the biggest consideration. "Intensity, hue, and purity of color are paramount," says Kurganoff. "A 5-carat diamond with extraordinary color can fetch more than a 15-carat diamond with a weaker saturation."
That's followed by what she calls "rarity of combination" and auction dynamics.
"An old Mine Fancy Vivid Blue over 20 carats is virtually unheard of. It's not just the size - it's the rarity of that size combined with vivid color and antique provenance.
"The alignment of vivid saturation, large size, provenance and antique cutting makes the Golconda Blue a once-in-a-generation, or even once-in-history, occurrence in the fancy color diamond segment. It cannot be overstated."
But even that level of rarity is no guarantee that it will meet or beat its high estimate.
"The final price often reflects competition on the day," she says. "Without enough highly motivated bidders, even a masterpiece may sell below expectations. Conversely, with strong buyer interest, bidding wars can escalate prices beyond any estimate."
The Golconda Blue has a rich heritage - recovered from the famed Indian mine after which it is named, acquired almost a century ago by Indian royalty, set in a necklace, then a brooch (by Harry Winston) and latterly as a ring, by JAR.
In terms of records, it's up against two other fancy vivid blues - the Cullinan Blue and the Oppenheimer Blue, both of which fetched $57.5m, give or take a decimal place or an exchange rate discrepancy.
The Oppenheimer Blue (14.62 carats, VVS1) - named after the one-time De Beers boss Sir Philip Oppenheimer - fetched CHF 56,837,000, equivalent to $57,541,779, when it was sold at Christie's Geneva in May 2016 (that's $3.9m per carat).
Then in April 2022 the Cullinan Blue (15.10 carats, IF), recovered by Petra Diamonds from the iconic Cullinan mine, in South Africa, sold for HK$450.9m at Sotheby's Hong Kong, equivalent to $57,471,960 ($3.8m per carat).
According to these figures the Cullinan Blue was pipped at the post, by a mere $69,819 - or just over 0.1 per cent of the purchase price.
And so to the Golconda Blue. It weighs in at 23.24 carats, which is 35 per cent more than the Cullinan Blue. As we've seen above, size is just one factor, so we can't simply do the math, on which basis we'd predict a price tag of $77.6m.
But who's to say it won't sell for even more? Tobias Kormind, managing director of London-based online diamond jeweler 77 Diamonds, believes it could realistically sell for $100m - more than any other diamond ever.
"With its pitch perfect provenance and unprecedented size at this quality, it is poised to blow every diamond ever auctioned out of the water to become the first $100m diamond ever sold at auction - and the most expensive diamond ever auctioned," he said.
How does he square that with Christie's more modest estimate ($35m to $50m)?
"Auction houses often give a lower estimate to ensure as much active bidding as possible and attract as many bidders as possible," he says.
"The estimates are rarely a true reflection of the actual market value. Typically for diamonds, they are listed between a third and half of their market value.
"Given this diamond's excellent provenance, both geological in terms of Golconda, and actual royal heritage and links to Harry Winston as well as its extraordinary carat weight, it's hard to imagine it won't achieve $4m per carat."
The auction takes place on 14 May. Watch this space.
Have a fabulous weekend.