The UAE, the world\'s fourth-largest oil exporter, is rapidly becoming a force in trade of another highly valuable commodity: diamonds. Dubai handled $35 billion (Dh128.5 billion) worth of rough and polished diamonds in 2010, a leap from an annual figure of just $3 million a decade ago, according to Malcolm Wall Morris, chief executive of the Dubai Multi Commodities Centre (DMCC). In the first half of this year Dubai traded $25.3 billion, a 55 per cent increase from the same period a year earlier. Much or most of the rise was due to surging diamond prices rather than growing volumes — but the increase nevertheless underlined Dubai\'s success in competing with other trading centres. \"Part of the UAE\'s policy is to diversify its income and gradually move away from one or a few sources of income,\" UAE Minister of Economy Sultan Bin Saeed Al Mansouri told Reuters on the sidelines of a diamond exhibition in Dubai. \"So there must be manufacturing and other sources of income we can depend on and that are also sustainable.\" The DMCC, which provides the infrastructure for commodities trade in Dubai, now ranks the emirate as the world\'s fourth largest diamond trading hub, behind Antwerp, New York and Mumbai. Antwerp, through which more than half of the world\'s diamond production passes, saw $48 billion of trade in the first ten months of 2010, according to data from the Antwerp World Diamond Centre.