Johannesburg – An exceptional 29.6-carat blue diamond has been discovered at the Cullinan mine in South Africa. 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, said Petra Diamonds Limited, which owns the Cullinan mine, in a statement here Tuesday. Petra … [Read more...] about Exceptional 29.6-carat blue diamond found in SA