Sotheby’s to auction rare 12ct ‘Blue Moon’ diamond

Auction house Sotheby’s Geneva is set to auction the rare ‘Blue Moon’ diamond with an estimated value of $35-55m (£22.6m-£35.4m).

The diamond is the centrepiece of the ‘Magnificent Jewels’ auction and Noble Jewels in Geneva on November 11. It weighs 12.03 carats and has been graded ‘fancy vivid blue’, the highest possible colour grading for blue diamonds.

The cushion brilliant-cut stone also boasts exceptional clarity, having been declared “internally flawless” by the Gemological Institute of America (GIA).

David Bennett, worldwide chairman of Sotheby’s international jewellery division, said: “The tremendous excitement last year over the discovery of a 29.62-carat blue rough diamond at the Cullinan mine in South Africa has now been proved to have been totally justified.

“Weighing in at 12.03 carats, the ‘Blue Moon’ diamond is a simply sensational stone of perfect colour and purity, combined with a superb cushion shape. Blue, for me, is the most mysterious and magical of all the colours of diamond, and the Blue Moon will now take its place among the most famous gems in the world.”