Mellon blue, one diamond vivid blue color, weighing 9.51 carats, sold for more than $25 million today (11.11.2025) in Geneva, Switzerlanda price in line with initial estimates for a gem of “excellent clarity,” according to auction house Christie’s.
The value of this blue diamond, set in a ring, is “among the most beautiful colored diamonds ever offered at auction,” according to Rahul Kandakia, head of Christie’s Jewelery in Switzerland.
The value of the diamond was estimated by the auction house at between 20 and 30 million dollars.
It went under the hammer for 17.4 million Swiss francs, with a final price of $25,592,269 after taxes, according to Christie’s.
The same gem, then known as the Zoe Diamond, was sold for $32.6 million by Sotheby’s in New York in 2014, setting world records for a blue diamond and price per carat at the time.
The stone was owned for decades by Rachel Lambert Mellon, better known as Bunny Lambert Mellon (1910-2014), a garden designer, philanthropist and collector of American art. Then the stone decorated a pendant.
Bunny Mellon is best known for redesigning the White House Rose Garden in 1961 at the request of President John F. Kennedy.
The highest price at a Christie’s auction for an intense blue diamond was achieved in Geneva in 2016, when the ‘Oppenheimer Blue’ (14.62 carats) was sold for $57.5 million.