The 9.51-carat “Mellon Blue” diamond sold for $25.5 million at Christie’s Geneva Magnificent Jewels auction, held Tuesday at the Four Seasons Hotel des Bergues.

The fancy vivid blue pear-shaped diamond boasts VVS1 clarity and the potential to be internally flawless. Recently mounted at the tip of a diamond-paved ring, it achieved Christie’s third-highest price for a vivid blue diamond sold at auction, selling within its estimates. The gem is most closely associated with Rachel Lambert “Bunny” Mellon (1910–2014), the American horticulturalist, philanthropist and art collector, who originally had it set as a pendant.

The Mellon Blue was previously sold by Sotheby’s in 2014—then unnamed—for more than $32.6 million, setting a world auction record at the time for any blue diamond. Its $3.3 million-per-carat price also established a record for price per carat for any diamond at the time. Then weighing 9.75 carats, it remains among the highest prices ever achieved for a fancy blue diamond.

The Geneva sale, comprising approximately 108 lots, featured jewels from private collections of royal and noble provenance, a trove of fancy-colored diamonds and creations by the celebrated French American high jewelry artist Joel A. Rosenthal from a single collector.

Fourteen of the sixteen JAR pieces offered—all but one from a single-owner collection—found buyers. (Christie’s initially said the single-owner collection included 25 pieces.) The top JAR lot, and the second-highest overall, was a pavé-set ring with round sapphires and diamonds centered by an 8.68-carat fancy purplish-pink diamond. It sold for $3.1 million, within its estimate.

Other notable JAR results included a pair of 18k rose gold and silver earrings set with zircons, sapphires, pink and green sapphires, aquamarines and diamonds, which fetched $476,660, exceeding expectations; and a “Papillon de Nuit” (moth) brooch composed of petrified wood, colored sapphires and spinels that sold for $286,000.

One of the most anticipated pieces before the sale—a brooch centered with a 65.46-carat cushion-shaped unheated Burmese “royal blue” sapphire surrounded by nine diamonds—failed to find a buyer. It had been estimated at $2.6 to $3.8 million.

The third-highest lot of the sale was a silver and gold star pendant-brooch, circa 1880, centered with a 10.07-carat oval-shaped ruby and adorned with old- and rose-cut diamonds. It achieved more than $2.85 million.

The pendant was among several Victorian-period jewels inherited by Helena Violet Alice, the third Countess of Stradbroke (1874–1949). Other highlights from the Countess’s “casket” of jewels included:

  • A silver and gold brooch, circa 1890, centered with a 7.88-carat cushion-shaped ruby set with old-cut diamonds, which sold for over $1 million—triple its high estimate.
  • A silver and gold tiara, circa 1880, adorned with rubies and diamonds, featuring a 4.02-carat Burmese ruby, which sold for $715,000, also above estimates.

The countess wore all three jewels at the coronation of King Edward VII in 1902, according to Christie’s.

Other highlights of the auction included:

  • A platinum and diamond necklace by Ronald Abram featuring a 36.20-carat heart-shaped brilliant-cut diamond of D color and VVS1 clarity, which fetched more than $2.7 million.
  • A pair of 18k white gold and platinum earrings by Fred, featuring a suite of pear-shaped brilliant-cut diamonds weighing between 2.39 and 10.69 carats, which sold for more than $2.3 million.
  • “The Rainbow Collection,” comprising more than 300 colored diamonds and treated colored diamonds spanning the full chromatic spectrum—red, blue, green, yellow, orange, pink and gray—curated for their singular hues, which achieved more than $2.2 million.

In total, the Christie’s Geneva Magnificent Jewels auction achieved more than $75.8 million.