The rare stone was discovered at its Cullinan mine, 40 kilometres north-east of Pretoria, and represents one of the most exceptional stones recovered at Cullinan during Petra's operation of the mine. Indeed it isn’t the first of its kind, what with the company having also unearthed a 25.5 carat blue diamond in 2013, which went on to sell for $16.9 million. Understandably the company’s latest discovery is also expected to sell for a substantial price.
"The stone is an outstanding vivid blue with extraordinary saturation, tone and clarity, and has the potential to yield a polished stone of great value and importance," Petra said in a statement.
Cullinan mine has been responsible for producing hundreds of large stones and is famed for its production of blue diamonds, which are among the rarest and most highly coveted of all diamonds. A similar 26.6 carat blue rough diamond discovered by the company in May 2009 was cut into a near perfect stone and fetched just under $10 million at a Sotheby's auction. Another deep-blue diamond from Cullinan was auctioned for $10.8 million in 2012, setting a world record for the value per carat.
Most famous of all however is without question the Star of Africa blue diamond, the world’s second largest cut diamond that was pulled from the Cullinan mine in 1905. The 530 carat stone would go on to be presented to King Edward VII and ultimately form part of the British crown jewels.
