The 5.18ct fancy blue vivid diamond was the first of the De Beers Millennium Blue diamonds to go under the hammer since they were sold to private collectors at the turn of the century.
The diamond exceeded pre-auction estimates that had given the rock an estimated sale value of US$5.8 million (£3.8 million).
De Beers Diamond Institute president Andrew Coxon was the visionary behind the collection and personally selected the roughs and worked with Steinmetz to ensure that they were cut with maximum beauty.
Talking of the sale, Coxon said: “The timeless beauty of a De Beers selected Millennium Blue diamond will be remembered long after its near record-setting price has been forgotten. Personally, I wish I could have bought it back for De Beers, but professionally speaking, I sincerely congratulate the new owners and I am happy that the new owners appreciated this particular De Beers selected diamond.”
