Editor’s Note
This article highlights the upcoming Christie’s auction featuring the exceptional “Mellon Blue” diamond, a headline lot for collectors and connoisseurs of rare gems.
A magnificent blue diamond and many extraordinary jewels are featured in Christie’s “Magnificent Jewels” auction.
An exceptional 9.51-carat Fancy Vivid Blue diamond is up for sale at Christie’s. This is the Mellon Blue, the auction house’s first flagship jewel for the second half of 2025. The stone has been graded “Internally Flawless” and is set as a ring. The diamond will be auctioned as part of the Magnificent Jewels sale on November 11 at the Four Seasons Hotel des Bergues in Geneva. This type of diamond is exceptionally rare, and this specimen captivates with its intense color and extraordinary purity.
What is it worth? Experts estimate its value at $20 to $30 million. It owes its name to the fact that the stone, previously set as a pendant, belonged for decades to Rachel Lambert Mellon, better known as Bunny Mellon (1910–2014), a wealthy American philanthropist and art collector. The Mellons are a wealthy and influential American family from Pittsburgh, Pennsylvania, active in banking and finance, business, and politics. Bunny Mellon was considered a symbol of elegance and refinement. The diamond was last publicly presented in 2014 when it was auctioned in New York, achieving one of the highest prices ever paid for a colored diamond at auction.
Christie’s auctioned nine of the ten most valuable jewels in the first half of the year – a 25% increase compared to the previous year. Two separate, owner-led live auctions in New York and Geneva achieved 100% sales. We now look confidently towards the second half of 2025 and announce the Mellon Blue.
Rahul Kadakia, International Head of Jewelry at Christie’s
Alongside the stunning blue diamond, the “Magnificent Jewels” auction includes three significant private collections.
A magnificent casket of family jewelry contains ruby jewels that are part of a prestigious ensemble inherited by Helena Violet Alice (née Fraser), 3rd Countess of Stradbroke (1874–1949). These pieces are among the finest surviving examples of Victorian craftsmanship and are distinguished by gemstones of a size and quality rarely found outside royal collections of that era. At the coronation of Edward VII in 1902, the Countess wore the ruby and diamond star brooch (estimated value: $1,400,000–$2,000,000), complemented by the royal ruby and diamond tiara (estimated value: $360,000–$600,000).
Rainbow Collection: Eddy Elzas entered the Antwerp diamond trade at a young age, beginning his career as a diamond cutter before moving into brokerage. In the early 1970s, during a stay in South Africa, he was shown a cigar box full of colored diamonds – stones that had found no buyers and were then considered less valuable than white diamonds. For Elzas, however, these were not rejects but the beginning of something new.
The Rainbow Collection is one of the largest and most conceptually coherent private collections of colored diamonds. It comprises over 300 natural stones of various cuts and carat sizes, covering the entire color spectrum: red, blue, green, yellow, orange, pink, and gray. Each diamond was selected for its unique and inimitable color nuance (estimated value: $2,000,000–$3,000,000).
Also on offer at Christie’s: the second-largest Jar collection ever auctioned, with 25 exceptional pieces. The collection is led by an 8.68-carat natural purplish-pink diamond ring (estimated value: $2.5–3.5 million), which emulates the Marie-Thérèse diamond (which set a new auction record for a Jar jewel at nearly $14 million at Christie’s New York in June).
Other objects in the catalog include:
• A 65.46-carat cushion-shaped brooch with an untreated Burmese royal blue sapphire, surrounded by nine significant colorless diamonds (estimated value: $2,600,000–$3,800,000).
• A Burmese ruby star brooch with a 10.07-carat oval brilliant at its center, set with old cushion- and rose-cut diamonds, worn by the Countess of Stradbroke at the coronation of Edward VII (estimated value: £1,400,000–£2,000,000).
• An Art Nouveau flower brooch by Tiffany & Co. with a demantoid garnet at its center (estimated value: £110,000–£150,000): designed by Paulding Farnham for Tiffany & Co. in 1901. With the turn of the century, design taste shifted away from the delicate, feminine aesthetic of the Victorian era towards bolder, more colorful expressions. This new direction included a revival of Renaissance styles, and Farnham became a leading figure in the American interpretation of this trend.