London: Colored gemstone miner Gemfields reported emerald and beryl production from its Zambian subsidiary Kagem Mining Limited jumped to 7.5 million carats in the first quarter to September 30, a 19 percent surge from a year ago. The average grade rose 11 percent to 237 carats per tonne. Revenue from its predominantly higher-quality rough emerald auction in Singapore in September was $34.7 million, the company said in a statement.

Ruby and corundum output from Mozambique-based Montepuez Ruby Mining Limited plunged 83 percent to 500,000 carats. However, the volume of higher-quality rubies recovered soared 96 percent, the company said. Overall, the average grade plummeted 83 per cent to 7 carats per tonne.

“Demand for colored gemstones continues to be firm as we look forward to our next lower-quality rough emerald and beryl auction later this month and our next auction of predominantly higher-quality rubies from Montepuez in December 2015,” Gemfields CEO Ian Harebottle said in the statement.

In September, the group sold $440,000 of higher-quality rough amethyst from its 50 percent-owned Kariba mine in Zambia at an auction in Singapore. The average realized price was $0.04 per carat, with 11 out of 16 lots sold, it said.

Gross profit from the company’s Faberge brand climbed 61 per cent from a year earlier. Gross margin advanced 21 percentage points to 51 percent, the company added in the statement.