The world of fine jewellery has always been one of constant one-upmanship (who doesn’t want to boast about a bigger, brighter, bolder diamond?), but every now and then along comes a piece that makes everyone truly stop and stare. Such is the case with The Art of de Grisogono, a new auction which will feature the largest, flawless D-colour diamond ever to cross the saleroom floor. (For the uninitiated, D-colour is best in class, and means the stone is completely colourless.) By the time it finally comes under the hammer, the diamond will be better travelled than most of you and your friends. Discovered in Angola, analysed in Antwerp and cut in New York, it is suspended in a necklace that is about to begin an international tour to Dubai, Hong Kong and finally Geneva, where it will be sold to the highest bidder on November 14.