A rare blue diamond called the “Mellon Blue” was sold for $25 million at an auction in Geneva on November 11, 2025. The diamond is 9.51 carats, has a perfect internal clarity, and a bright blue color that collectors highly value.
The diamond was set in a ring with a swirling design. It once belonged to Rachel “Bunny” Mellon, a well-known philanthropist and art collector who passed away in 2014 at the age of 103. The diamond was originally a pendant and was later made into a ring.
In 2014, the same diamond was sold for $32.6 million, which was a record price for colored diamonds at that time. Even though the 2025 sale was lower, it still shows that rare blue diamonds are in strong demand. The world record for a blue diamond is still held by the “Oppenheimer Blue”, which sold for over $57 million in 2016.
Experts say the diamond’s bright blue color, perfect clarity, and famous history all made it very valuable. “Internally flawless” means the diamond has no visible flaws when viewed closely. The fact that it belonged to Bunny Mellon adds to its appeal and price.
The auction in Geneva attracted many collectors and investors who are interested in rare colored diamonds. This sale shows that these gems are not only beautiful but also considered a good investment. Gems with history and fame often sell for higher prices.
Even though the diamond did not reach its 2014 price or the world record, it still highlights how rare and important such gems are. For auction houses and collectors, the Mellon Blue sale proves that top-quality diamonds with a famous history can attract millions of dollars.
