A Lost Royal Tiara, a Coronation Opal & Queen Mary's Pearls Are All Hitting the Block

Geneva's "Royal Week" Is About to Begin

Every November, the world's great auction houses converge on Geneva — and in 2026, the story is royalty. Over two sales just days apart, Phillips (its Geneva Jewels Auction VII on Monday, November 9) and Sotheby's (its Royal & Noble Jewels sale on Wednesday, November 11) are offering a parade of jewels tied to emperors, empresses, duchesses and queens. Several have been off the market for a generation or more — and at least one vanished from public view for nearly seven decades.

These are the pieces that stop a saleroom cold: a Cartier opal tiara worn at two British coronations, a long-lost diamond tiara made for a French royal wedding, and a pearl necklace that once belonged to Queen Mary. The announcements rolled out across late October and into this week; the hammers fall next week. Here's your field guide — and why royal provenance can turn a beautiful jewel into a record-breaker.

Cartier Black Opal and Diamond Tiara/Necklace. Photo Credit: SOTHEBYS.

The Devonshire Opal Tiara — Worn at Two Coronations

The star of Sotheby's sale is the Cartier "Devonshire" black opal tiara, created by Cartier London in the late 1930s and set with a suite of rare Australian black opals accented by diamonds. It belonged to Mary Cavendish, Duchess of Devonshire, and it carries a provenance that most jewels can only dream of: it was worn at the 1937 coronation of King George VI and again at the 1953 coronation of Queen Elizabeth II. Cleverly made, it can be taken apart and worn as a necklace and brooches.

Sotheby's estimate: CHF 780,000–1,100,000 (roughly $980,000–$1.4 million). Black opal is a fragile, temperamental gem rarely seen at tiara scale — pairing that rarity with a double-coronation history is exactly the kind of story that pushes bidding past expectations.

A Diamond Tiara Lost Since 1958

The most romantic lot may be the Mellerio "Orléans" diamond tiara, made around 1862 by the Place Vendôme house Mellerio dits Meller for that year's London International Exhibition. Set with old-mine and rose-cut diamonds (reported at roughly 110–125 carats total) and convertible into a necklace, it was given in 1864 by Antoine d'Orléans, Duke of Montpensier, to his daughter Marie Isabelle for her marriage to Philippe d'Orléans, Count of Paris.

From there the trail gets cinematic. The tiara descended through the Orléans family and was worn into the 1950s by the Marchioness of Valdeterrazo — and after her death in 1958, it simply disappeared from public view. Nearly seven decades later, it resurfaces at Sotheby's with an estimate of CHF 300,000–500,000. A royal jewel, lost for a lifetime, walking back into the light: that's the kind of headline that sells catalogs.

Queens, Empresses & the Rest of the Royal Lineup

Over at Phillips on November 9, the headline provenance is Queen Mary's: a Hennell cultured pearl and diamond necklace from 1928 — made as a tribute to Queen Victoria's Golden Jubilee necklace, strung with 21 pearls — which Queen Mary gave to her niece, the Duchess of Beaufort. It's estimated at CHF 120,000–180,000 and hasn't been offered in about 20 years. The same Phillips sale is also offering a historic emerald and diamond bracelet linked to Empress Eugénie of France, whose largest emerald weighs about 5.46 carats.

Back at Sotheby's, the royal roll call keeps going — from Empress Maria Feodorovna's 197-carat Romanov Sapphire to emeralds once owned by Queen Amélie of Portugal. (We covered the Romanov Sapphire in detail right here last week — it's part of this very sale.) Here's how the headline lots stack up:

The cultured pearl and diamond necklace, formerly in the Collection of Mary of Teck, Queen of the United Kingdom. Photo Credit: Christies.

What a "Royal Week" Really Means for the Rest of Us

You may never bid on a coronation tiara — but these sales still matter if you love jewelry, because they quietly set the rules for how all fine jewelry is valued. Here's what this week is really telling us.

That last point is the one we love most. The jewels crossing the block in Geneva are extraordinary, but the instinct behind them is universal: we hand down the pieces that hold our stories. If you have an heirloom you'd love to wear again — a tired setting, a strand of pearls that needs restringing, or a stone you'd like reimagined — a thoughtful custom redesign in our Incline Village studio can give it a second act. Royalty optional.

History You Can Wear, in Lake Tahoe

You don't have to fly to Geneva to own a jewel with a story. At Forever Rox Fine Jewelry, we've been helping Lake Tahoe families choose, restore, and reimagine meaningful pieces since 1984. Whether you're curious how provenance and rarity shape value, hunting for an estate piece, or ready to turn a family heirloom into something you'll actually wear, we'd love to help you write the next chapter.

Frequently Asked Questions