Francis Oats was a Cornish miner who became chairman of De Beers diamond company. He made extensive investments in the Cornish tin mining industry, which collapsed after he had died. He is known for Porthledden, a mansion he built at the tip of Cornwall.

The De Beers Group is a South African- British corporation that specializes in diamond mining, diamond exploitation, diamond retail, diamond inscription and grading services, diamond trading and industrial diamond manufacturing sectors. The company is active in open-pit, underground, large-scale alluvial and coastal mining. It operates in 35 countries with mining taking place in Botswana, Namibia, South Africa, and Canada. It also has an artisanal mining business, Gemfair, which operates in Sierra Leone.