Auction introduction: Christie’s Magnificent Jewels auction returns to Geneva this November 2025, following the success of the May sale which totalled USD 72,3M selling 100% by lot including an auction record price per carat for a Fancy Deep Blue diamond mounted by Boucheron. The auction at the Four Season Hotel des Bergues in Geneva features a curated selection of historic and modern jewellery from all periods as well as the most famous jewellery houses such as Harry Winston, Cartier, JAR, Van Cleef & Arpels, and many more. The highlight of the Magnificent Jewels auction is THE MELLON BLUE — an exceptional Fancy Vivid Blue diamond, weighing 9.51 carats, standing out as one of the finest coloured diamonds ever to appear on the market (estimate $20,000,000 – 30,000,000). For decades the stone belonged to Rachel Lambert Mellon, better known as Bunny Mellon (1910-2014), an American horticulturalist, philanthropist, and art collector.