‘Mellon Blue’ diamond fetches $26.6 million at Geneva auction

A 9.51-carat fancy vivid blue diamond, known as the ‘Mellon Blue’, sold for 20.5 million Swiss francs ($26.6 million) at Christie’s auction in Geneva on Tuesday (11 November), including fees. The pear-shaped gem had been estimated to sell between $20 million and $30 million.