SINGAPORE (Aug 19): A new exchange offering diamonds as an asset class to investors is off to a quick but small start in Singapore, with trading turnover at a bit more than US$3.4 million ($4.6 million) in the first two weeks of August, up from US$1 million in all of May, its first month of trading.

Singapore Diamond Investment Exchange, or SDiX, is one of a handful of players around the world trying to entice investors to put money in diamonds rather than other commodities like gold and silver.

The potential is huge, but SDiX's small start shows how difficult it can be to break into an industry where supply is overwhelmingly dominated by a few global companies and buying and selling is established in a closed-door system of behind-the-scenes negotiations.