Christie’s will offer a rare and historic blue diamond in its upcoming Magnificent Jewels sale on November 11, with the exceptional stone estimated to fetch up to $30 million.

Known as the Mellon Blue, the jewel features a 9.51-carat, pear-shaped, fancy vivid blue diamond, graded internally flawless — one of the highest accolades for clarity and color in the diamond world.

The diamond was once owned by Rachel Lambert “Bunny” Mellon, the American philanthropist, art collector, and noted horticulturalist whose garden designs can be seen at both the White House and the Palace of Versailles. Mellon, heiress to the Gillette fortune, was known for her refined taste and cultural influence.

Previously set in a pendant, the diamond was sold at Sotheby’s in 2014 for $32.6 million, where it set a then-world record for a blue diamond. It has since been recut to enhance its clarity, and is now being presented in a newly designed ring setting for this sale.

“This stunning fancy vivid blue diamond, which once belonged to America’s ‘Garden Queen,’ is among the finest colored diamonds ever to come to market,” said Rahul Kadakia, International Head of Jewelry at Christie’s. “After a very strong first half for Christie’s jewelry department, we look forward to the second half of 2025 with great confidence.”

Ahead of the auction, Christie’s will preview the Mellon Blue in Saudi Arabia, Shanghai, Hong Kong, Bangkok, and New York, allowing collectors and connoisseurs around the world a rare glimpse at one of the most exquisite colored diamonds to appear at auction in recent years.