Former US President Bill Clinton was keynote speaker at a gala dinner in this port city, famous for its diamond trade, telling industry leaders that as the illicit trade became globalised, global cooperation was needed to fight it.
The goal of the conference was how to better market and boost sales of the gems worldwide, especially in the industry's key market, the United States.
But doing that means the industry has to live up to the "highest ethical standards," said Keith Johnson, from Anglo-Australian mining giant Rio Tinto.
While not on the official agenda, the issue of blood diamonds continues to shadow the industry. While it "has done a great deal," consumers must be convinced that the industry has cleaned up its act, said the managing director of De Beers, Gary Ralfe.
De Beers, the industry leader, estimates that trading in blood diamonds accounted for up to 4% of the annual global trade in rough diamonds, but believes that new controls are turning things around.
Revelations over the past decade that diamond sales were financing deadly conflicts in Angola, Sierra Leone, Congo and Liberia dimmed the industry's image, threatening sales and forcing the introduction of new controls.
The industry is also confident that diamonds are not funding terrorist groups either. Industry experts however, believe the issue, as well as a global economic downturn has left scars. Diamond traders, retailers and producers have felt the pinch from weaker consumer demand and a glut of polished gems now on the market.
"The past two years have not been the easiest," said Peter Gross, head of diamond and jewelry group at Dutch bank ABN-Amro, citing the September 11 terrorist attacks and the Iraq war as depressing sales.
Buying up an excess supply of polished diamonds, with slow demand, has forced many dealers to go out of business, and has left a total industry debt hovering around US$8.6bn, Gross said.
The industry, which was worth some $7.8bn in 2002, is expected to grow in the years ahead after three years of restructuring to change the way diamonds are sold, polished and marketed.
From the start of this year, each diamond has to be accompanied by a certificate of origin. A total of 45 countries have signed on to implement the agreement.
Last week in South Africa, participants agreed to a system of voluntary reviews by fellow members.
Upon the request of member countries, review teams will be dispatched to evaluate compliance with the tracking system.
Ten countries have already offered to submit themselves to review, including Congo, where diamonds continue to be traded for arms, according to a recent UN-commissioned report.