GENEVA - A vivid blue diamond weighing 9.51 carats and previously belonging to Rachel “Bunny” Mellon, the aristocratic philanthropist and a close friend of Jacqueline Kennedy, sold in Geneva for US$25 million (S$32 million), Christie’s auction house said on Nov 11.

The internally flawless pear-shaped diamond mounted at the tip of a swirling ring design is named the “Mellon Blue,” after its former owner who had it set as a pendant. It sold for US$32.6 million in 2014, the year Mellon died at the age of 103.