The exceptional diamond, receiving $463 965/ct, was recently recovered from Petra Diamonds' Williamson mine in Tanzania, East Africa.
The diamond was purchased by Golden Yellow Diamonds on behalf of M.A. Anavi Diamond Group - a leading diamond manufacturer and specialist in large and unique coloured diamonds.
Petra will receive 10% of the value uplift of the polished diamond.
In December 2015, Petra Diamonds sold another exceptional 23.16 ct pink diamond, also recovered from the Williamson mine, into a partnership deal for $10.05 million, or $433 938/ct, with Golden Yellow Diamonds.
Petra retained a 20% interest in the sales proceeds of the polished diamond.
The Williamson mine, located upon the 146 ha Mwadui kimberlite pipe, is renowned for beautifully rounded white goods and ‘bubblegum’ pink diamonds, including the 23 ct Williamson Pink (54 carat rough stone), which is considered to be one of the finest pink diamonds ever recovered.
Cartier, London, 1953 Diamonds, platinum 10 × 5.5 cm
The Williamson Diamond is considered the finest pink diamond ever discovered. It was found in October 1947 at the Mwadui mine in Tanganyika, owned by the Canadian geologist and royalist Dr John Thoburn Williamson (1907–58), after whom the diamond was named.
The rough, weighing 54.5 Ct, was presented by Dr Williamson, as a wedding present to Princess Elizabeth in 1947.
The stone was cut by the firm of Briefel and Lemer of Clerkenwell into a 23.60 Ct round brilliant, maximising its luxurious rose colour.
Queen Mary and Princess Elizabeth inspected the work of cutting and polishing during a visit to the Clerkenwell premises on 10 March 1948. When the Queen acceded to the throne in 1952, there was speculation that the stone might be mounted for use at the coronation. However, it was instead set as the centre of a brooch in the form of a jonquil flower, designed by Frederick Mew of Cartier, in 1953.
Dr Williamson wished to add further pink diamonds to his original gift, but as these were not available, he gave The Queen 170 small brilliant-cut diamonds, 12 baguette-cut diamonds and 21 marquise diamonds, which were used to form the petals, stalk and the leaves of this brooch.