Even in the busy world of global auctions, a Hong Kong sale in April of a famous diamond promises to be a scene-stealer.

In the steady diet of news about art auctions and other sales of beautiful objects, it is sometimes easy to become rather blasé over the Picassos, Ferraris and Patek Philippes that are sold for eye-popping sums. But there is an auction in the pipeline that promises to be one of the top events of the calendar. 

Sotheby’s Hong Kong is presenting the “De Beers Millennium Jewel 4”, a rare oval-shaped “internally flawless fancy vivid blue diamond” weighing 10.10 carats, making it the largest oval-shaped such diamond ever to appear at auction. It carries a sales estimate of HK$235 – HK$280 million ($30 – $35 million). The diamond is up for sale at the suitably-named Magnificent Jewels and Jadeite Spring Sale on 5 April.

The diamond, on sale from an Asian private collection, is the only oval-shaped stone among the 12 rare diamonds - 11 blue and one colourless – that form the world-renowned De Beers Millennium Jewels collection unveiled by De Beers in 2000 in celebration of the millennium.