Editor’s Note
A historic blue diamond, once part of Bunny Mellon’s collection, returns to auction in Geneva this November. Having set a world record price of $32.6 million in 2014, its reappearance promises to be a landmark event in the world of rare gems.
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Once owned by the horticulturalist, collector and philanthropist Bunny Mellon, this pear-shaped blue diamond realised $32.6 million when it was offered from her collection in 2014 — at that time a world-record price for a blue diamond. It returns to auction in Geneva on 11 November 2025.
A sensational coloured diamond and diamond ring. Fancy vivid blue modified pear brilliant-cut diamond of 9.51 carats, single-cut diamonds, platinum. Sold for CHF 20,525,000 on 11 November 2025 at Christie’s in Geneva.
In November 2014, following the death of the horticulturalist Rachel Lambert Mellon — better known as ‘Bunny’ — more than 1,500 items from her personal collection went to auction in New York.
An icon who lived to the age of 103, Mellon was celebrated for designing the White House’s Rose Garden at the request of her friends John F. and Jacqueline Kennedy. She owned a formidable collection of art and many breathtaking homes, and was renowned for her insouciant style.
Truman Capote told Time magazine that she always carried a pair of scissors with her so that ‘when things look a little too neat, she can take a little snip out of a chair or something so that it will have that lived-in look’.
Estimates started at just a few hundred dollars for one of her watering cans, climbing all the way to $20 million for Rothko’s Untitled (Yellow, Orange, Yellow, Light Orange). The proceeds, Mellon had declared in her will, would fund a foundation to promote the power of gardens to improve wellbeing.
On the evening of 20 November, and the following morning of 21 November, a dedicated section of the sale offered more than 250 of Mellon’s jewels — a substantial part of a collection so vast and exquisite that it has since passed into the realm of folklore.
wrote Meryl Gordon, the author of Bunny Mellon: The Life of an American Style Legend.
As a result — and thanks to an almost unlimited budget supplied by her second husband, the Pittsburgh banking heir, philanthropist, art collector and racehorse breeder Paul Mellon — her shopping sprees were nothing short of heroic.
The couple were the largest spenders with Fulco di Verdura, a Sicilian duke and jeweller who opened a store in Manhattan in 1939. Among the jewels he made to order for Bunny Mellon were a spray of purple amethyst flowers, an apple-tree brooch adorned with 26 ruby fruits, and a rhinoceros table decoration carved from a single block of blue rock crystal.
Down the road at Tiffany’s, Mellon’s Christmas list could be up to 35 items long, spanning everyone from her mother to her manicurist, with items costing up to $100,000 each.
She also acquired no fewer than 140 pieces by her close friend Jean Schlumberger, many of which were design collaborations. Among them were custom clips for her Dior handbags, a dancing starfish made from rubies and diamonds, bracelets adorned with turquoise and sapphire butterflies, and a potted sunflower ornament constructed from gold, diamonds and emeralds.
revealed Pierce MacGuire, the former director of Tiffany’s Schlumberger salon, to Gordon that Mellon wanted to possess virtually every design the jeweller had created, yet often didn’t even take them home.
Possibly Mellon’s most extravagant purchase, however, was a pear-shaped blue diamond weighing a prodigious 9.75 carats.
says Max Fawcett, head of Jewellery at Christie’s in Geneva, where the diamond is being offered for sale once more, on 11 November 2025.
The stone’s rich colour has been classified ‘Fancy Vivid’, a rare category that accounts for less than one per cent of all blue diamonds, which are already incredibly elusive. It has also been graded ‘Internally Flawless’.
The last time the stone was seen in public was at Mellon’s 2014 auction, where it was photographed alone on the front cover of the catalogue for her jewellery sale.
In Gordon’s biography, she noted how, prior to the auction, the media’s glowing coverage stressed two themes: Mellon’s magnificent taste, and how much she abhorred attention.
Town & Country called it ‘the auction of the decade’. Meanwhile, the Financial Times in London noted: ‘Before her death, few things were known about Bunny Mellon. She was more interested in climbing trees than in climbing the social registers.’ Appropriately, little is known of where she acquired the gem, or when she wore it.
After its sale in 2014, the Mellon Blue was retouched to improve its clarity and reset in a serpentine pavé ring engraved with the words ‘Fancy Vivid Blue’.
