A model holds a De Beers cushion brilliant-cut fancy vivid blue 5.53 carats diamond that could fetch 15 million US dollars during a press preview by Sotheby's auction house ahead of sale in Geneva on November 3, 2022. - The stone is part of eight rare Fancy Blue diamonds to be sold across its jewels auctions this year in New York, Geneva, and Hong Kong and throughout the Spring of 2023. (Photo by Fabrice COFFRINI / AFP)