(IDEX Online) - Petra saw revenue from rough diamond sales fall by almost a third at this month's tender, down to $42.3m from $61.3m in October/November.The volume sold in Tender 3 FY23 was also down by almost a third as per carat prices remained virtually unchanged. The UK-based miner said the earlier cut-off date for the current cycle was largely to blame for the lower sale. They were down two thirds on the previous December.Petra, which operates three mines in South Africa and one in Tanzania, said in three tenders so far this financial year it had sold no exceptional stones, compared with almost $78m in the same period last year."!Although it is still too early to speculate on whether rough diamond prices have bottomed out, we are very satisfied with the overall result," said CEO Richard Duffy."Prices in the 2-ct to 10-ct size ranges saw an upward movement in contrast to the recent negative trends, partly ascribed to improving expectations for the current festive season and potentially reflecting signals from the Chinese authorities with respect to an easing of lockdown restrictions."Pic, courtesy Petra, shows the Koffiefontein mine