One of the world’s most remarkable coloured diamonds is set to take centre stage at Christie’s Geneva this autumn. “The Mellon Blue” — a 9.51-carat fancy vivid blue diamond once owned by philanthropist and renowned horticulturalist Rachel Lambert “Bunny” Mellon — will headline the auction house’s magnificent jewels sale on 11 November.
The pear-shaped stone, now mounted as a ring, has been graded Internally Flawless and is expected to achieve between US$20m and $30m. Exceptionally rare for both its intensity of colour and purity, it is among the finest blue diamonds ever to appear at auction.
The stone was last publicly seen in 2014, when it fetched US$32.6m at Sotheby’s New York, setting a world record for a blue diamond at the time. Since then, it has been re-cut to improve clarity, slightly reducing its weight from 9.75 to 9.51 carats.
Bunny Mellon, who died in 2014 aged 103, was widely admired for her refined taste in art, interiors and gardens. Her celebrated commissions include redesigning the White House Rose Garden at the request of President John F. Kennedy in 1961, and contributing to projects at Versailles and the home of couturier Hubert de Givenchy.
Rahul Kadakia, Christie’s international head of jewellery, said: “After a particularly strong first half of the year, we look confidently to Geneva with the Mellon Blue, a truly extraordinary diamond once belonging to America’s Garden Queen.”
The stone will be previewed in Hong Kong in October. (Photo courtesy: Christie’s)
22-09-2025
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