The 9.51-carat Mellon Blue diamond sold for CHF20,525,000 (US$25,592,269) at Christie’s Magnificent Jewels auction in Geneva on November 11, 2025. The commonly reported $25.5 million figure is rounded; the Associated Press says its dollar total includes the buyer’s premium and other fees.
What is the Mellon Blue diamond?
The Mellon Blue is a pear-shaped, Fancy Vivid Blue diamond. Christie’s identified the stone as weighing 9.51 carats at the 2025 sale and named Rachel Lambert Mellon, better known as Bunny Mellon, as a previous owner. Christie’s lot history describes it as internally flawless. Christie’s lot history
How did the sale compare with its estimate and earlier auction?
Christie’s had estimated the diamond at US$20 million to US$30 million before the 2025 auction. It had previously sold at Sotheby’s in 2014 for $32.6 million, when it weighed 9.75 carats, according to Christie’s and the Associated Press. At the 2025 sale it weighed 9.51 carats. The reported figures and weights establish the two auction outcomes, but the sources do not explain the price difference; they do not support a conclusion about its cause or the stone’s investment performance. Christie’s lot history · Associated Press, November 11, 2025
Where does the Mellon Blue rank among Christie’s vivid blue diamond sales?
Christie’s said the result was the third-highest price for a vivid blue diamond sold at Christie’s. In the auction house’s cited comparison, the Oppenheimer Blue sold for US$57.5 million in 2016 and the 17.61-carat Bleu Royal for US$39.5 million. These are Christie’s ranking comparisons, not a comprehensive ranking across auction houses. Christie’s sale result and ranking
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