Christie’s have launched a new publicity blitz with the unveiling of the sale of another remarkable stone: the Cullinan Dream Diamond. At 24.18 carats, it is the largest blue diamond ever to be offered up to auction. Christie’s have a good track record with record breaking stones, having sold to date the largest vivid orange, vivid green, vivid blue and vivid red diamonds. The clarity of the diamond has not yet been revealed, and nor has the official pre-sale estimate.

The Cullinan Dream, second from left, flanked by its three sister stones.

It will be interesting to see what price the stone achieves: the record per carat to beat will be that held by the Fancy Intense Blue VVS1 stone weighing 1.74 carats which Christie’s sold last year. This stone fetched an eye watering $1.106 million a carat and was rather ignored by the media. One can only assume it was due to lack of provenance or its perceived modest size. Stone dealers will be keeping an extra close eye to the results of this sale not only because of the importance of the stone but because of the spectacular flop that was the sale of the Shirley Temple Blue diamond last month at Sotheby’s. The pre-sale estimate of this much hyped gem was $25-35 million; bidding stalled at £22 million and the jewel was withdrawn. Although apparently money is not an issue for the seller, there will be expectations to sell the Cullinan Dream for a high price- as we know, coloured diamonds have no pricing index like regular commodities and the price per carat achieved will underpin the future prices of other important coloured diamonds.

The Cullinan Dream is the largest of four main stones that were cut from a rough weighing 122.52 carats. This whopper was discovered in the South African Cullinan mines owned by Petra Diamonds. The most remarkable thing about blue diamonds from this mine is that they are specifically extracting colourless stones, so any blue ones discovered are pure chance.