Mellon-choly: Diamond Auction Has Some Feeling Blue

By Rob Bates | November 13, 2025

On Nov. 9, Christie’s Geneva sold the Mellon Blue, a 9.51 ct. internally flawless fancy blue pear-shape, for $25.6 million—an impressive number that some still considered disappointing.

That final price landed right in the middle of the auction house’s presale $20 million to $30 million estimate, and is the most Christie’s has scored for a jewelry piece this year.

Yet in 2014, when the auction market was far frothier, Sotheby’s sold the Mellon Blue for $32.6 million—setting a per-carat record for a colored diamond of $3.3 million. The buyer was later identified as fugitive Hong Kong billionaire Joseph Lau, who renamed it the “Zoe Diamond” after his younger daughter.

Although the latest sale means the value of the gemstone has dropped by some $7 million since then, Rahul Kadakia, president of Christie’s Asia Pacific and chairman of its global luxury group, tells JCK: “The Mellon Blue achieved $25 million at Christie’s and $30 million the first time it was offered for sale. At this level, I would say the result is very comparable.

“The buyer at the first sale was the seller and did not participate, and we worked with different collectors this time. [A] 10 to 15% [difference] at elite levels is always expected.”

While the Mellon Blue auction attracted “frenzied bidding,” the result was far from “dazzling,” according to Tobias Kormind, managing director of online jeweler 77 Diamonds.

“Geopolitical tensions, from the war in Ukraine to Trump’s tariffs and a weakened Chinese economy that kept many usual buyers away, left the room distinctly cautious,” Kormind said in a statement. “Today’s muted performance was a disappointment, and whether this restraint will ripple through the rest of the Geneva season remains to be seen.”

The fancy vivid blue diamond was named after its onetime owner, the late Rachel Lambert “Bunny” Mellon, a philanthropist and friend of Jacqueline Kennedy Onassis. Bunny’s husband Paul was heir to the Mellon banking fortune.

Overall, Christie’s Geneva Luxury Week sale fetched $102 million, a 24% increase over last year.

(Photo courtesy of Christie’s)