A diamond bandeau tiara commissioned from Boucheron in 1924 — and not seen publicly since — sold to Boucheron’s Heritage Department for its private collection for $681,764 (converted from £508,400) at Bonhams’ June 11 Exceptional Jewels auction. The final sale price was more than the pre-sale estimate of $270,000 to $400,000 (converted from £200,000 to £300,000).
The tiara’s openwork design features scrolls, quatrefoils, and stylized olive leaf motifs graduating in size toward the center pear-shape diamond, a 3.6 ct. old brilliant-cut stone. According to Bonhams, Boucheron received the commission shortly before a family wedding.
“Bonhams’ Exceptional Jewels sale in London features no less than six distinguished and private single-owner collections, with many fine examples of antique, 20th century, and signed jewels,” said Jennifer Tonkin, the auction house’s head of jewelry in the U.K., in a statement.
Lots spanned the Napoleonic era to the 21st century, and included elaborate diamond pieces, noteworthy colored stones, and jewels from the top maisons.
From the early 20th century, Bonhams offered a Belle Époque seed pearl and diamond sautoir by Cartier that came from the estate of Dame Nellie Melba (1861–1931), a celebrated Australian opera singer. Signed Cartier Paris and featuring seed pearl linking punctuated by millegrain-set diamond spacers, suspending a pierced circular diamond pendant, the sautoir achieved $170,843 (converted from £127,400).
The most historically charged lot may have been a diamond jewel bearing a miniature watercolor-on-ivory portrait of Russian emperor Alexander I, believed to have been presented to him as a diplomatic gift during his state visit to England in 1814. The portrait diamond jewel earned $136,782 (converted from £102,000).
Henry Addington, 1st Viscount Sidmouth—a former prime minister of the U.K.—was involved in arranging the state visit, and the jewel enters Bonhams’ auction from the Sidmouth family. Surrounding the portrait are four principal cushion-cut diamonds of 1.1 to 2.8 cts., along with approximately 18.75 cts. t.w. old brilliant diamonds.
Also in the sale from the Sidmouth family collection: a circa 1870 gold flexible-link bracelet bearing three flowerheads, convertible to a brooch and hair ornaments, set with over 21 cts. diamonds (estimate £15,000–£20,000) — sold for $42,912 (converted from £32,000 — and a pair of 19th-century diamond pendent earrings (£10,000–£15,000) — sold for $48,061 (converted from £35,840.)
This is an updated version of an article that first published on JCKonline.com on June 10, 2026.
(Photos courtesy of Bonhams)
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