Rare 9.51-carat Mellon Blue diamond fetches $25.6 million at Christie’s

A model wears a ring set with the Mellon Blue, a 9.51-carat Fancy Vivid Blue diamond graded Internally Flawless and estimated at $20-30 million, during an auction preview at Christie's in Geneva, Switzerland, November 7, 2025. — Reuters The Mellon Blue, a 9.51-carat fancy vivid blue diamond that once belonged to US art collector Bunny Mellon, sold for $25.6 million at auction on Tuesday. The...