The Cartier Opal Tiara Worn at Queen Elizabeth II’s Coronation Heads to Sotheby’s Geneva

The most storied jewel of Geneva’s November auction week has already been to two coronations. Sotheby’s will offer the Devonshire Cartier opal tiara — an Art Deco black opal and diamond tiara that converts into a necklace and brooches — at its Royal & Noble Jewels sale in Geneva on November 11, 2026, with an estimate of CHF 780,000–1.1 million (about $945,000–$1.3 million).

Photo Credit: Courtesy of Sotheby's

Cartier made the piece around 1937 for Mary Cavendish, then Marchioness of Hartington and later Duchess of Devonshire. Sotheby’s says it was most likely commissioned for the coronation of King George VI that year. According to family tradition, the black opals were presented to the Marquess and Marchioness during a government tour of Australia and New Zealand in 1936–37, and the client supplied them to Cartier herself.

The jewel’s second coronation was the bigger one. In 1953, Mary Cavendish, by then Dowager Duchess of Devonshire, served as Mistress of the Robes to Queen Elizabeth II and walked just behind the Queen and her train-bearers in the procession. She wore the opal necklace with the Devonshire palmette tiara, and Sotheby’s calls it one of the most prominently featured jewels of the ceremony, second only to the Queen’s own.

Photo Credit: Courtesy of Sotheby's

The design is built for versatility. Five detachable brooches each center an oval black opal, set with old mine-, old European- and single-cut diamonds and accented by baguettes, with a pear-shaped diamond at the front. It comes with a tiara fitting and a devant-de-corsage fitting for the three central brooches, in a fitted case stamped Cartier. The jewel was shown in the Victoria and Albert Museum’s Cartier exhibition in London in 2025, and on February 5, 2026, director Emerald Fennell wore the necklace to the London premiere of her Wuthering Heights adaptation.

The supporting cast leans just as royal. A diamond tiara by Mellerio dits Meller, created for the London International Exhibition of 1862, was given in 1864 as a wedding gift to Marie Isabelle of Orléans when she married the Count of Paris; its Greek key design also detaches to be worn as a necklace, and it carries an estimate of CHF 300,000–500,000 (about $365,000–$605,000).

Photo Credit: Courtesy of Sotheby's

Marie Isabelle’s eldest daughter, Amélie of Orléans, the last Queen of Portugal, is represented by an antique emerald and diamond bangle from the 1880s whose detachable center holds a 27.38-carat Colombian cabochon emerald, estimated at CHF 70,000–100,000 (about $85,000–$120,000). Other highlights include a toi et moi ring pairing a 7.83-carat Kashmir sapphire with a 6.77-carat Colombian emerald, linked by Sotheby’s to Catherine Walston, the inspiration for Graham Greene’s The End of the Affair (CHF 350,000–500,000, or about $425,000–$605,000), and a Bucherer necklace centered on a 43.07-carat Ceylon sapphire (CHF 320,000–480,000, or about $390,000–$580,000).

Photo Credit: Courtesy of Sotheby's

Provenance is the whole proposition here. Sotheby’s describes the sale as an annual tradition of its November Geneva Luxury sales, and it says the last three editions have achieved white-glove status. A Cartier jewel worn at the 1953 coronation and on a red carpet in 2026 is exactly the kind of lot that makes that streak worth watching.

Highlights are on view at Sotheby’s Zurich, Rämistrasse 3, through October 23 and at The Gallery – Ital Auto Ferrari in Singapore from October 22 to 25. The full sale is on view at the Mandarin Oriental, Geneva, from November 6 to 10, 10 a.m. to 6 p.m., ahead of the live auction on November 11 at 5 p.m. CET.

For more of Haute Living’s auction coverage, see the Bulgari Pink diamond heading to Christie’s Geneva and Christie’s Geneva jewelry auction preview.