Production at the Argyle diamond mine in Western Australia was 5.2 million carats in the first quarter of 2006, off 19 percent from the final quarter of 2005 and down 40 percent from the first quarter of 2005.

Production has been declining for years at the mine as the open pit is exhausted, and in the first quarter severe wet weather from cyclones was also a problem.

Rio Tinto plc, the owner of the mine, has decided to go to underground mining when the open pit is exhausted around 2008. The vast majority of the diamonds produced at Argyle, now and in the past, are of industrial quality, with only relatively small amounts of the famous Argyle pink and champagne-colored stones. Still, these are crucial for certain Indian diamond polishers.