It said in a statement that the mine’s grade also leaped from 236 carats per tonne of ore a year ago to 265 carats this year.
Unit production costs went down 34 percent to 56 cents per carat from $0.85 per carat in the quarter to 31 March 2012.
Gemfields said it recorded revenues of $15.2 million from the recent auction in Lusaka, a record for lower quality auctions.
This was despite a small drop in the average per carat price achieved, said company chief executive Ian Harebottle.
“We continue to seek to address the possible ban on foreign auctions by the Ministry of Mines in Zambia,” he said.
Meanwhile, the gemstone miner said that bulk-sampling operations at the company’s Mozambican ruby project were “progressing well” and had plans to hold its first ruby auction in about a year from now.
“Core infrastructure required for operations is largely established. A significant security presence has reduced the incidence of illegal mining. Primary stage mining and processing equipment is on site and operational,” it said.