BHP has been developing its own Canadian potash mine — the Jansen project — in Potash Corp's backyard, and has already invested about $3.8 billion on it.
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.
Brexit is a sideshow to the world economy, and gold remains an important asset in any portfolio, says Marc Faber, editor of the Gloom, Doom and Boom Report.