The head of the world's largest diamond company has urged traders to support the creation of diamond cutting and polishing centers in Africa.

Gareth Penny, managing director of the South Africa-based De Beers company, said it is not altruism, but good business sense to create new jobs in fledgling African democracies.

Penny spoke Monday at a diamond industry conference in Antwerp, Belgium.

The conference also heard from a Botswanaian mining industry official, Kago Moshashane, who said his country is planning to create thousands of new jobs in the diamond processing industry.

But activist and former pop star Bob Geldof argued that African economies cannot grow on natural resources alone. He called for a Marshall Plan for Africa, like the one that helped resurrect Europe after World War II.

Sierra Leone, Liberia and Angola are among diamond-producing African countries that have recently emerged from years of conflict. Diamond wealth often fueled the fighting, leading to international efforts to outlaw the sale of illegally mined gemstones.

De Beers is the world's largest diamond miner and producer. It controls about 40 percent of the world's diamond industry.