Rare pink diamond given to Queen Elizabeth sells for over £400m

An extremely rare fancy vivid pink diamond sold for 453 m Hong Kong dollars 52 m more than double its estimated price and set a world record for the highest price per carat for a diamond sold at auction.

The 11.15-carat Williamson Pink Star diamond, named after another pink diamond given to Queen Elizabeth II as a wedding gift, was sold to an unidentified buyer at auction by Sotheby s Hong Kong on Friday.

The stone's link to the late monarch is likely to have helped elevate its value, according to Tobias Kormind, the managing director of London jewellery shop 77 Diamonds.

He said that this is an astonishing result, proving the resilience of top diamonds in a shaky economy. When you consider an alluring link to Queen Elizabeth, rising prices for pink diamonds due to their increasing rarity and the backdrop of an unstable global economy are some of the things that attract people to the Queen Elizabeth.

Some of the world's highest quality diamonds have seen prices double over the last 10 years. The cushion-shaped diamond is named after two other large pink diamonds: the 59.60 carat, mixed-cut, oval pink star diamond sold at auction in 2017 for $71.2 m then 57 m and the Williamson stone, a 23.60 carat diamond given to the Queen in 1947 by Canadian geologist and ardent royalist John Thoburn Williamson.

The Williamson was designed by Frederick Mew, of Cartier, in 1953, and is said to have been a favourite of the late Queen, who wore it on many occasions during her reign, including the silver jubilee.

Williamson owned the Mwadui mine in Tanzania, where the Williamson stone and the Pink Star were discovered.

Wenhao Yu, chair of jewellery and watches at Sotheby s Asia, said that the discovery of a gem-quality pink diamond of any size is an extremely rare occurrence, something that with the closure of the Argyle mine until recently was highly improbable. Argyle, a Rio Tinto-owned diamond mine in the remote north of Western Australia, closed in 2020 after 37 years of operation. It produced more than 865 m carats of rough diamonds.

Pink diamonds are particularly rare among coloured diamonds and no one knows how they become pink geologically.

While nitrogen and boron are responsible for the vivid hues of yellow and blue diamonds, there is no evidence that pink diamonds receive their colour from trace elements, Sotheby s said.

The crystal structure of the stone selectively absorbs light as a result of an idiosyncratic lattice defect, which results in an unusual arrangement of atoms in the crystal. These happy anomalies can cause pink graining in the diamond crystal a perfectly brilliant display of imperfection.