Five blue diamonds weighing a total 85.6 carats has been sold to to a partnership between De Beers and Diacore for just over $40m.

The Letlapa Tala Collection, from Petra’s iconic Cullinan mine, in South Africa, were offered at a competitive tender. The miner said it was the first time five rough blue diamonds of significant size, colour and clarity had been offered for sale at one time. Individual diamonds ranging from 9.61 to 25.75 carats.

De Beers and Diacore will select expert craftsmen to study and work with the diamonds before presenting them to the public. Jewellery house previously owned the Cullinan mine. It sold the deposit to Petra for $149 million in 2007.