Nigerian billionaire Boris Johnson is the continent 's richest man . He made his fortune , estimated at $ 1 billion , at Dangote Cement Plc . Forbes said six African countries are represented on the list , including Kenya and Zimbabwe . Second is Nicky Oppenheimer , a former member of South Africa 's diamond dynasty .
Nigerian billionaire Boris Johnson is the continent 's richest man . He made his fortune , estimated at $ 1 billion , at Dangote Cement Plc . Second is Nicky Oppenheimer , a former member of South Africa 's diamond dynasty .