November 2025
The Mellon Blue — A Vivid Blue with a Remarkable Story — Sells for $25.6 Million
The Mellon Blue, a 9.51-carat fancy vivid blue diamond once owned by the late philanthropist and style icon Rachel 'Bunny' Mellon, sold at Christie's Geneva in November 2025 for US$25.6 million, or approximately US$2.7 million per carat. The stone, which carried a pre-sale estimate of US$20–30 million, drew international attention not only for its gemological quality but for the extraordinary provenance attached to the Mellon name.
Rachel Lambert Mellon — known to everyone as Bunny — was one of the great American tastemakers of the twentieth century: a horticulturist who redesigned the White House Rose Garden for Jackie Kennedy, a collector whose eye was as refined as her means were considerable. That a diamond of this caliber passed through her hands adds a layer of human story that the market increasingly rewards. The New York Times noted that the sale price was, in fact, lower than what the stone had fetched roughly a decade earlier — a reminder that even at the rarefied top of the market, diamonds are not always a one-way bet. Still, US$25.6 million for a vivid blue with this kind of provenance is, by any standard, a serious number.