(Fortune Magazine) -- Conflict diamonds, the stones sold to finance some of the bloodiest wars in Africa, should be history. But a recent USAID report on Sierra Leone - where these men were sifting old mine tailings for stray diamonds this summer -concluded that as many as 50% of the country's diamonds are still smuggled out.

That's despite efforts by international organizations and market leaders such as De Beers to clean up the $50 billion diamond jewelry business. Sierra Leone, where 68% of the people live in poverty, funded its late-'90s civil war with the gems.

Horrified, the UN imposed sanctions, and industry and NGOs formed the Kimberly Certification Process, which has reduced the share of conflict stones from 4% to 1% of global supply. "The challenge is to ensure good diamonds aren't tainted by conflict diamonds," says Jacob Thamage, a Kimberly group official. "Diamonds are our sustenance."

The issue will be back in the public eye this fall with the release of "Blood Diamond", a Warner Bros. thriller in which Leonardo DiCaprio searches for a rare pink dazzler in Sierra Leone. News of the film prompted De Beers and its allies to take out full-page ads and launch an "education" website in the hope that diamonds, about half of which are sold in the United States, won't become blemished by the moral stain that has made fur an object of fury rather than envy.