Geneva’s prestigious November auction season is set to dazzle the world once again, with the spotlight firmly on one of the rarest gems ever to appear on the market the 9.51-carat “Mellon Blue” diamond. This exceptional Fancy Vivid Blue diamond, expected to sell for between US$20 million and US$30 million, will take centre stage at Christie’s Magnificent Jewels Auction on 11 November.
The “Mellon Blue” was once part of the private collection of Rachel “Bunny” Mellon, the American philanthropist, horticulturist, and style icon whose refined taste defined 20th-century elegance. The pear-shaped gem exemplifies the extraordinary rarity and beauty of natural blue diamonds, a category that represents less than 0.02% of all diamonds mined worldwide. Its vivid saturation, flawless symmetry, and provenance place it among the most significant blue diamonds ever graded.
According to diamond experts, Fancy Vivid Blue diamonds of this size and clarity are virtually never seen at auction. Certified by the Gemological Institute of America (GIA), the Mellon Blue ranks alongside legendary stones such as the Oppenheimer Blue and De Beers Blue, both of which achieved record-breaking prices exceeding US$50 million.
Following Christie’s event, Sotheby’s Geneva will host its own major sale featuring the 10-carat “Glowing Rose” pink diamond and a selection of historic royal jewels once owned by Napoleon Bonaparte. Together, these back-to-back auctions reaffirm Geneva’s status as the global epicentre of fine jewellery and rare diamond sales.
The Diamond Certification Laboratory of Australia (DCLA) notes that the increasing global demand for coloured diamonds, particularly blue and pink stones, continues to drive record prices across international auctions. With limited supply and strong interest from collectors and investors alike, these rare gems remain among the most secure and sought-after assets in the luxury market.
For more updates on the world’s most important diamond discoveries, auctions, and grading insights, visit DCLA News — Australia’s trusted source for verified diamond information and international market trends.