Lusaka: Gemfields achieved a record average price for “higher-quality” rough emerald at an auction in Lusaka, Zambia.

The miner sold 470,000 carats for an average of $70.68 per carat at the sale in Lusaka, which ran from March 30 to April 3. Total revenue generated was $33.1 million.

Gemfields said production of emeralds and beryl at the Kagem mine in the African nation slumped 28 percent to 7.1 million carats in the first quarter that ended March 31. Output of ruby and corundum from Montepuez surged 43 percent to 2 million carats.