The ambitions of Mumbai's diamond traders are grand, even if their offices are not. They nurse dreams of rivalling Belgium's Antwerp as the world's diamond trading capital while sitting in ageing tower blocks that are about as grimy as a cut diamond is sparkly. Corridors are splattered bloody red with decades' worth of spat-out chewing tobacco. Lift doors must be yanked shut by hand. Toilets must be entered gingerly. Traders' offices, though somewhat cleaner than the public spaces, tend to be cramped. But, barring any last-minute bureaucratic spanners, the bulk of the trade should soon shift across the city to a new home more befitting one of India's biggest export earners. India already polishes about nine in every ten diamonds, mostly tiny, cheaper stones less than a carat. Faced with growing global competition, India hopes to cling on to its position in polishing by spreading into an area in which it has lagged: the trade of rough diamonds. “We're trying to make India the largest trading center and manufacturing center for diamonds,” said Sanjay Kothari, the chairman of India's Gem & Jewellery Export Promotion Council (GJEPC). “Why should we go to Antwerp?” A bullish confidence is common among Indian businessmen these days. Nonetheless, even if few see Antwerp being eclipsed any time soon, the ambition of Kothari and his colleagues is giving pause to at least some Antwerp traders. In 2006-2007, India imported $8.8bn of rough diamonds and exported $10.9bn of polished gems, much of which is sent to Hong Kong and the United States to be set in jewellery. But its dominance is under threat. Consultancy firm KPMG said in a 2006 report that India's share of diamond polishing by value would drop to 49 percent by 2015, from 57 percent today, as the global diamond industry spreads into new corners of the globe. China is investing heavily in polishing mid-sized stones. Angola, Namibia and Botswana are increasingly determined to process locally some of the stones chipped from their mines, which once would have been promptly whisked off to the London clearing house of De Beers, the dominant player in rough trade. To keep their foothold, India intends to spread out along the chain between mines and ring fingers. Indians' success in cutting diamonds has given them advantages elsewhere: about 40 percent of the trade in Antwerp is controlled by Indians, according to the GJEPC's Kothari, while Indians make up about half of De Beers' elite customer list. The new Bharat Diamond Bourse – Bharat being the Hindi name for India – will house India's first international diamond trading hall, and is intended to bring the trade back to the land where diamonds are said to have been first mined a millennia ago. “Finally!” exclaimed Louise Prior, a spokeswoman for the De Beers' marketing arm the Diamond Trading Company (DTC), when told by a reporter the bourse's opening may be imminent. “It's been under construction for a seriously long time.” In fact it has been about 15 years, a few years less than it took to build the Taj Mahal, and its blue, glassy, cliff-sized facade already looks a little dated.