From the archives: Harry Levy of the Gemological Association of Great Britain provides some interesting commentary on diamonds, regulation, traceability of diamonds, and the KP:

Wars occur without the presence of diamonds; it does not follow that if there are diamonds then war will ensue. The rebels themselves say that if there were no diamonds they would use other natural commodities to obtain money. The diamond industry has been maligned for years now as a source of evil and too many people with absolutely no knowledge of the diamond industry and trade have jumped in to try to make our world a better place. There seems to be little equivalent activity to control the oil industry and, more important, the arms industry.

via WFDB

Via RoughDiamondGeologist:

Unfortunately, from almost day one, the Kimberley Process was a very sad joke. Diamonds continued to flow from conflict countries. At first, it was circumvented within the diamond manufacturing industry. There were mining companies and their customers who put profits ahead of the well-being of those who were being tortured and killed. They simply shipped the diamonds to non-conflict countries and had the Kimberley Certificates issued in those countries.