It was found at Petra's Cullinan mine in South Africa, which has yielded several massive gems, including the largest rough gem diamond ever discovered.
The history of the diamond industry in Africa has been fraught with worker exploitation, environmental destruction, government corruption and squandering of revenues.
Kinross, which operates two mines in Russia and also owns the problem-plagued Tasiast operation in Mauritania, seeks to strengthen its portfolio in North America.
Moody's says AngloGold Ashanti, Gold Fields will start spewing cash as gold price rise and currency falls combine – for Anglogold it's an extra $20m a month.