Cleaver takes on the new role at a difficult time for De Beers as Diamond sales stagnated in 2015, hit by a weaker Chinese economy. However, producers are seeing scope for recovery, especially in the United States, which accounts for some 45 percent of demand.

Anglo American, which has an 85 percent stake in De Beers -- the world's largest diamond producer by value -- is focussing on the diamond business after a restructuring.

Cleaver, 51, was previously group director of strategy and business development at De Beers. He will take over the role on July 1, the company said on Friday.

He succeeds Philippe Mellier, 60, who is stepping down saying he had envisaged his job as a five-year plan.

"Having steered through some of the diamond industry's toughest times and with the market showing signs of recovery, now is the right time for me to pass the baton to the next generation," he said in a statement.

Mark Cutifani, Chief Executive of Anglo American and Chairman of De Beers, said Cleaver, offered "strong continuity at an important stage in the diamond market's recovery".

Cleaver first joined De Beers' board in 2008 and served as its co-acting CEO in 2010 before Mellier's appointment.

"He is a very solid internal choice for what is arguably the key division," Jeremy Wrathall, analyst at Investec, said.

Investec has predicted De Beers will transform the shape of Anglo American as the firm, battling with high levels of debt following the commodities rout, shifts towards diamonds and platinum and away from more industrial assets such as coal.

(Reporting by Mamidipudi Soumithri in Bengaluru and Barbara Lewis in Brussels; Editing by Philip Blenkinsop and Alexander Smith)