Sotheby's Auctions Cartier Opal Tiara Worn at Coronation
A Cartier opal and diamond tiara worn by Mary Cavendish at Queen Elizabeth II's 1953 coronation goes to auction in Geneva.
Updated on Nov. 2, 2026 in Jewelry
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Sotheby's is auctioning a Cartier opal and diamond tiara made in 1937 for Mary Cavendish, later Duchess of Devonshire, who wore it at Queen Elizabeth II's 1953 coronation. Sotheby's estimates the piece will sell for 780,000 to 1,100,000 Swiss francs.
Why it matters
The tiara is one of the lead lots in Sotheby's Royal and Noble Jewels sale, offering collectors a rare chance to acquire a piece tied to a major royal ceremony. Its link to Australian opals also highlights the gemstone's origins, as Australia produces about 95% of the world's opals.
The tiara is made of five detachable brooches, each centered on an oval black opal surrounded by diamonds, and can be worn as brooches, a tiara, a necklace, or a corsage ornament. Sotheby's estimates a sale price of 780,000 to 1,100,000 Swiss francs, or about $950,000 to $1.4 million, and the final price remains unknown until bidding closes.
The players
Sotheby's
Sotheby's is a global auction house that runs specialized jewelry sales, including the Royal and Noble Jewels sale featuring this tiara.
Cartier
Cartier is a French luxury jeweler founded in Paris in 1847 and known for its high-end diamond and gemstone pieces.
Emerald Fennell
Emerald Fennell is a British filmmaker and director known for her work on high-profile film projects, who wore the opal necklace to a premiere.
The details
Cartier made the piece in 1937 using six opals that Mary and her husband received during a government tour of Australia and New Zealand in 1936 and 1937. Mary served as Mistress of the Robes at the 1953 coronation, wearing the opal necklace with the Devonshire diamond tiara, and the auction is being held at Sotheby's in Geneva this month.
Timeline
1936 and 1937: Mary and her husband receive opals during a government tour of Australia and New Zealand.
1937: Cartier makes the tiara for Mary Cavendish.
1953: Mary wears the opal necklace at Queen Elizabeth II's coronation.
February 2026: Director Emerald Fennell wears the opal necklace to the London premiere of Wuthering Heights.
November 2026: The tiara is auctioned at Sotheby's in Geneva.
Royal Jewelry Market
Royal coronation jewels have become prominent lots at major auction houses, as Sotheby's Royal and Noble Jewels sale shows with this tiara worn at the 1953 coronation of Queen Elizabeth II. The sale's inclusion of pieces owned by the late Princess Birgitta of Sweden extends this pattern of royal-linked jewelry reaching the open market.
Collectors and jewelry enthusiasts worldwide can follow the Geneva sale to see how royal-linked pieces are valued. Readers interested in buying or appraising similar antique jewelry can use this estimate as a reference point for opal and diamond pieces of the period.
The takeaway
Royal-linked jewelry can carry significant value at auction, so collectors should research provenance and comparable sales before bidding. Opal pieces in particular depend on stone quality and origin, making expert appraisal essential.
Further reading
Explore more in our Jewelry section for additional context on fine gems and collectible pieces.
Source note: This article includes information reported by Town & Country.
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