Opponents of a move to allow Zimbabwe diamonds to be certified as "conflict-free" held their ground during a meeting of the World Diamond Council in St. Petersburg, Russia.  The dispute could limit the ability to regulate trade of the stones.

Members of the diamond industry, governments and civil groups met for a second day this week to try to come to a consensus on whether to approve raw diamonds from Zimbabwe's Marange fields to be exported and sold.

Parties involved in the talks are members of the Kimberley Process - an initiative to ensure the diamonds sold in markets around the world are not used to finance rebel groups warring against legitimate governments.

The broad majority supports certification for Marange diamonds, saying they meet the minimum requirements, and the diamond trade could help Zimbabwe's faltering economy.

But the opposition argues government forces that control the Marange fields are committing human-rights violations there.  

The complaint does not exactly fit the Kimberley criteria for "conflict diamonds", but members of the industry say the issue should still be sorted out under the authority of the Kimberley Process.

World Diamond Council vice president, Sergey Oulin, the host of the St. Petersburg meeting, says if the Kimberley Process fails to resolve this situation, it would be its biggest failure in history.

Kimberley participants met previously on this issue in June, but failed to reach unanimous consent needed for certification.

Oulin says if they do not find a compromise solution, they will lose any authority they have over the situation.

He says the question is whether we participate in that process as active members, or allow natural events to resolve it for us; then we will just have to follow the outcome, and our opinion will not matter.

One possible outcome is that Zimbabwe will trade the diamonds without Kimberley certification, as President Robert Mugabe has promised to do.