Although River Diamonds is currently producing a few hundred gem diamonds a week, averaging 0.42 carats, and selling them at around $250 a carat, this is still a risky business, as highlighted by the story of the Cintra Larga tribe of Amazonian Indians who, in April, murdered 29 diamond miners 'riddling their victims‘ bodies with arrows, beheading several and using others for live target practice, to send a message to other miners to keep off Indian land,' according to a Daily Mail report.