(IDEX Online) - Petra saw rough prices dip by up to 18 per cent as it brought forward its Tender 2 ahead of India's voluntary two-month moratorium.The UK-based miner has sold 344,554 carats so far - three quarters of the total tender volume - for $30.2m and says it is currently offering the remaining 25 per cent. It will release full sales results in the next few days.The average price per carat on sales so far is $88, with like-for-like prices down by 16 per cent to 18 per cent compared to Tender 1 FY2024, reflecting prevailing market weakness.Among the goods sold were stones recovered from the Williamson mine, in Tanzania, which has been closed since a breach of its tailings dam last October.Petra said: "In the medium to longer term, we continue to expect prices to benefit from the structural supply deficit."File pic, courtesy Petra, shows 424.89 carat and 209.2 carat D-Color Type II diamonds recovered at Cullinan.