RAPAPORT... Weak rough prices pushed Rio Tinto's diamond unit into thered in the first half of the year, the miner reported Thursday. The division recorded a net loss of $5 million for the sixmonths ending June 30, compared with a profit of $55 million a year ago. Diamondsales fell 16% to $271 million for the period. Production dropped 10% to 8.3 million carats, primarily dueto a 13% decrease in output at the Argyle mine in Australia amid lower oregrades. Recoveries at the Diavik deposit in Canada fell 1%, as reduced grades outweighedhigher processing volumes. The miner maintained its overall production forecastof 15 million to 17 million carats for this year. Rio Tinto holds 100% of Argyle, as well as 60% of Diavik,which it owns in partnership with Dominion Diamond Mines. Image: An aerial view of the Diavik mine. (Dominion Diamond Mines)