The rise of rhodium, the world’s most expensive precious metal, has made it the No. 1 revenue stream of the biggest platinum miners. While the metal is well shy of its March peak, rhodium still accounted for 45% of Anglo American Platinum’s first-half revenues. That’s more than platinum and palladium put together. For parent Anglo American, the silvery-white metal generated more revenue than the diamonds mined by its De Beers business or the copper it extracts in Chile and Peru.