Blue-green diamond sells for $17.3 million at Geneva auction
The 5.50-carat Ocean Dream diamond nearly doubled in value since its sale in 2014.
A 5.50-carat natural blue-green diamond named the Ocean Dream sold for approximately $17.3 million at a Christie's Geneva auction in May 2026, according to the Times of India.
The gemstone, which is classified as a Fancy Vivid Blue-Green diamond, is considered the largest known diamond in its colour category. It features a triangular cut and an SI1 clarity grade.
The diamond's value has increased significantly over the last decade. In May 2014, the same stone fetched approximately $8.5 million at a Christie's Geneva auction.
The final sale price in 2026 exceeded the presale estimate of CHF 7 million to CHF 10 million. The stone fetched CHF 13.56 million during the recent auction.
Discovered in Central Africa during the 1990s, the original rough diamond weighed 11.70 carats. Its current weight is less than half of that original form.
The Ocean Dream was previously displayed at the Smithsonian National Museum of Natural History in Washington, DC, in 2003 as part of an exhibition titled The Splendour of Diamonds.