Editor’s Note
This article describes the record-breaking auction of the “Mellon Blue” diamond, a rare gem distinguished by its intense color and significant size, which captivated wealthy collectors and fetched bids in the millions.
With an unusually intense blue hue and a size that makes it even more coveted, this rare gem sparked million-dollar bids in a room filled with collectors and magnates.
The “Mellon Blue” diamond, weighing 9.51 carats, sold for US$25.5 million at Christie’s Magnificent Jewels auction in Geneva, held on Tuesday at the Hotel Four Seasons des Bergues. It is an intense blue, pear-shaped diamond with VVS1 clarity and the potential to be internally flawless. It was recently mounted as the centerpiece of a ring with a diamond pavé setting. It achieved the third-highest price ever paid at a Christie’s auction for an intense blue diamond and sold within its estimated range.
The stone is closely linked to Rachel Lambert “Bunny” Mellon (1910-2014), an American horticulturist, philanthropist, and art collector, who originally set it as a pendant.
The Mellon Blue had previously sold in 2014 through Sotheby’s, though unnamed at the time, for over US$32.6 million. That sale set a world auction record for any blue diamond. Furthermore, its price of US$3.3 million per carat also set a historic per-carat record for any diamond. With a weight of 9.75 carats, it still ranks among the highest prices achieved for an intense blue diamond.
The Geneva auction included approximately 108 lots and featured jewels from private collections of royal and noble provenance, a collection of fancy colored diamonds, and pieces created by the renowned Franco-American high jewelry artist Joel A. Rosenthal (JAR), all from a single collector.
Fourteen of the sixteen JAR pieces offered—all but one from that private collection—found buyers. Christie’s had initially reported the collection contained 25 pieces. The standout JAR lot, and the second most expensive of the auction, was a ring with a pavé of round sapphires and diamonds, featuring a fancy purple-pink diamond of 8.68 carats at its center. It sold for US$3.1 million, within the estimated range.
Other notable JAR results included a pair of 18k rose gold and silver earrings set with zirconias, sapphires, pink and green sapphires, aquamarines, and diamonds, which sold for US$476,660, above expectations. Another notable lot was a “Papillon de Nuit” (moth) brooch, crafted from petrified wood, colored sapphires, and spinels, which reached US$286,000.
One of the most anticipated pieces before the auction was a brooch featuring an untreated Burmese “royal blue” sapphire weighing 65.46 carats, cushion-shaped and surrounded by nine diamonds. However, it failed to find a buyer. Its estimated price ranged between US$2.6 and 3.8 million.
The third most expensive lot of the auction was a star-shaped brooch-pendant, made in silver and gold around 1880, with a 10.07-carat oval ruby at its center and decorated with old mine-cut and rose-cut diamonds. It sold for over US$2.85 million.
This piece was part of a collection of Victorian jewels that belonged to Helena Violet Alice, the third Countess of Stradbroke (1874-1949). Highlights from the Countess’s jewelry “coffer” included:
A silver and gold brooch, made around 1890, with a 7.88-carat cushion-cut ruby set with old mine-cut diamonds at its center, sold for over US$1 million, triple its high estimate. Also notable was a silver and gold tiara, from around 1880, adorned with rubies and diamonds, including a 4.02-carat Burmese ruby, which reached US$715,000, above expectations.
Other standout lots from the auction were:
A platinum and diamond necklace by Ronald Abram, featuring a 36.20-carat heart-shaped brilliant-cut diamond, D color and VVS1 clarity, which sold for over US$2.7 million.
Also notable was a pair of 18k white gold and platinum earrings by the firm Fred, featuring a series of pear-shaped brilliant-cut diamonds ranging from 2.39 to 10.69 carats. They sold for over US$2.3 million.
The so-called Rainbow Collection, consisting of more than 300 unmounted colored diamonds, sold for over US$2.2 million.