Diamonds, Napoleon brooch up for auction in Geneva

A Sotheby's employee displays an old mine-cut diamond brooch or pendant owned by Emperor Napoleon I, circa 1810, during a preview at Sotheby's in Geneva, Switzerland, Thursday, Nov. 6, 2025. (Martial Trezzini/Keystone via AP)

Geneva, Switzerland -- Spectacular diamonds valued at tens of millions of dollars will go under the hammer in Geneva next week, alongside a brooch seized from Napoleon as he fled the battle of Waterloo.

The unique brooch laden with old mine-cut diamonds, which has been valued at US$150,000 to $250,000, will be the star piece at Sotheby’s annual Royal & Noble Jewels sale in Geneva on November 12.

The historic jewel was among a number of prized personal belongings Napoleon Bonaparte had brought with him to Waterloo in 1815.

In his haste to flee as his armies were overwhelmed by the combined British and Prussian forces, the French emperor abandoned some of his carriages, including one carrying his precious belongings, when they got stuck in the mud a few miles (kilometres) from the battlefield.

The circular diamond brooch, around 45 millimetres in diameter, has at its centre a large oval diamond weighing 13.04 carats, surrounded by nearly one hundred old diamonds of varying shapes and sizes.

The piece, which was created for Napoleon around 1810, was offered along with other items to Prussian King Friedrich Wilhelm III as battle trophies on June 21, 1815, three days after the Battle of Waterloo.

Also going under the hammer at Sotheby’s auction next week is a 10.08-carat vivid pink diamond, named “The Glowing Rose”, which is expected to rake in around $20 million.

The gem “of exceptional quality” was named after its “extremely rare” luminous and pure pink colour, Sotheby’s said.

A day earlier, rival auction house Christie’s will be offering up a magnificent 9.51-carat vivid blue diamond, known as “The Mellon Blue”, expected to fetch up to $30 million.

The stone, set on a pendant, once belonged to Rachel Lambert Mellon, better known as Bunny Mellon, an American horticulturalist, philanthropist and art collector.

The diamond was last seen publicly in 2014, when it was offered at auction in New York after her death, for more than $32 million.

Tobias Kormind, head of Europe’s largest online diamond jeweller 77 Diamonds, said in a statement the stone “could well smash the world record for price per carat for any blue diamond at auction”.

That record, he said, is currently held by the Blue Moon of Josephine, which was sold for over $48 million in 2015, or $4.1 million per carat.