Petra Diamonds, owners of the Premier/Cullinan diamond mine since 2008, has announced the discovery of an extraordinary, 29.6-carat, rough blue diamond during their operations at the historic mine, situated 37 km northeast of Pretoria in South Africa’s Gauteng Province.
Commenting on their latest find, a spokesman of the diamond mining company said, “the exceptional acorn-sized diamond, small enough to fit into the palm of a hand, is an outstanding vivid blue stone with extraordinary saturation, tone and clarity, and has the potential to yield a polished stone of great value and importance. Blue diamonds are among the rarest and most highly coveted of all diamonds and the Cullinan mine is the most important source of blues in the world. This stone is one of the most exceptional stones recovered at Cullinan during Petra’s operation of the mine.”
Johan Dippenaar, CEO of Petra Diamonds, said, “the latest blue diamond discovery could outstrip recent finds. By some margin, this is probably the most significant stone we’ve ever, in terms of blue stones recovered. The stones in the last year or so are selling well above $2 million per carat. That’s not my quote, that’s updates in the market”
Some significant blue diamonds had been discovered at the mine, since Petra Diamonds began operations in 2008. In 2009, a 26.6-carat, vivid-blue rough diamond was discovered at the mine, which was cut and polished into a 7.03-carat, cushion-cut, fancy vivid-blue diamond and sold at a Sotheby’s Geneva auction in May 2009 for US$ 9.5 million. This diamond was subsequently christened the “Star of Josephine” diamond. Another notable diamond, recovered at the mine in April 2013, was the 25.5-carat rough blue diamond, known as the “Cullinan Blue” diamond, which was sold in the rough for US$ 16.9 milion. The 7.59-carat “Premier Blue” diamond, said to be the largest, round brilliant-cut, fancy vivid blue diamond in the world, and was put up for auction at the Sotheby’s Magnificent Jewels & Jadeite Autumn Sale on October 7, 2013, at Hong Kong, with a pre-sale estimate of US$ 19 million, is also believed to have originated in the Premier/Cullinan diamond mine.
Since the depletion of the main source of blue diamonds in the world in ancient times, the Kollur diamond mines in Golconda, in southeastern India, which produced famous blue diamonds such as the Hope, Tereschenko, Wittelsbach and Sutan of Morocco diamonds, the Premier/Cullinan diamond mine in South Africa, became the main souce of blue diamonds in the world in the 20th-century, a position which it still enjoys. Notable blue diamonds discovered at the Premier/Cullinan diamond mines include, the 30.82-carat, Blue Heart diamond; 30.06-carat Blue Lili diamond; 27.64-carat, Heart of Eternity diamond; 25.00-carat Transvaal Blue diamond; 20.02-carat, Graff Blue Ice diamond; 14.00-carat, Blue Empress diamond; 13.78-carat, Begum Blue diamond and the collection of 11 rare blue diamonds, known as the De Beers Millennium Collection displayed at the London Millennium Dome in the year 2000, together with the 203.04-carat, Millennium Star diamond.
Apart from rare blue diamonds, Premier/Cullinan diamond mine had been a prolific and consistent source of large colorless diamonds, including the world’s largest gem-quality rough diamond on record, the 3,106-carat Culinan diamond, that was subsequently cut into two of the most important diamonds in the British Crown Jewels, the 530-carat “Star of Africa” mounted on the Royal Scepter and the 317-carat, “Lesser Star of Africa” mounted on the band of the Imperial State Crown of Great Britain. The mine had produced over 750 stones weighing more than 100 carats, 130 stones weighing more than 200 carats, and around a quarter of all diamonds weighing more than 400 carats.
Blue diamonds are rare Type IIb diamonds, in which the presence of trace quantities of boron impurities not only imparts a blue color to the diamonds but also make them semi-conducting. Their occurrence in nature is much less than 0.1%, to the extent that only one significant blue diamond is said to be produced every year at the Premier/Cullinan diamond mine, the main source of blue diamonds in the world today, out of all the rough production in the mines for an year.
Analyst Cailey Barker at brokers Numis thought the diamond could fetch between $15 million and $20 million at auction.
Dippenaar said the company would decide what to do with the diamond in the next week.