Sotheby's, De Beers and the Business of Rare Colour

Sotheby's and De Beers have been circling the same idea for years: that the most compelling diamonds on the market today aren't necessarily the biggest, but the ones with a story attached.

In March 2026 the pair unveiled the 'Jwaneng 28.88' diamond, named for the Botswana mine that produced it one of the world's richest diamond deposits by value.

It's the kind of provenance play that colour-diamond specialists say increasingly drives bidding: buyers in Asia and the Middle East, in particular, have shown a long-running appetite for stones whose rarity is legible even to non-experts. With Sotheby's still holding four of the five most valuable jewels ever sold at auction, the house's continued partnership with De Beers looks less like a one-off and more like a standing strategy.