“In 2005, USAID’s Integrated Diamond Management Programme (IDMP) in Sierra Leone experimented with a diamond mining cooperative scheme in order to formalize and rationalize the artisanal sector, and increase local beneficial. Two American businessmen invested $55,000 and $20,000 into the scheme and recovered only $4,400 between them. Although the scheme was implemented for just one mining season, it was held up as a failure by the investors, USAID’s programme evaluators, and development professionals at-large. This paper gives an overview of the scheme, assesses its failures and successes, provides lessons learned, and considers whether or not cooperatives should be considered for artisanal diamond production elsewhere.”