Gemfields Grou. Share News (GEM)

Gemfields enjoyed a strong final quarter, during which the company held the first ever auction of rubies from its mine in Mozambique, the mining firm announced on Thursday.The auction delivered revenues of $33m (£19.6m) at an average realised price of $18.4 (£10.9) per carat.The company has confirmed one more ruby auction is scheduled for 2014.In the three months before June, Montepuez, Gemfields' Mozambican mine, saw its production of ruby and corundum fall from 1.1m to 0.2m compared to the same period 12 months ago, but Gemfields said the quality of the extracted product was much higher."Gemfields enjoyed a momentous quarter given the success of our inaugural auction of rough ruby and corundum from the Montepuez ruby deposit in Mozambique, held in Singapore," said Gemfields' chief executive officer Ian Harebottle."The auction represented a profound shift in the ruby industry and underscored the prospects of our model and vision for the coloured gemstone sector."The company's emerald mine at Kagem, Zambia, saw its production in the last quarter fall from 8.9m to 6.3m year-on-year, though Gemfields stressed the output was higher than in the previous two quarters.Emerald grade fell from 322 carats per tonne last year to 271, while costs rose from $1.01 per carat to $1.33 per carat.During the quarter, Gemfields said an auction in May of traded rough emeralds (not obtained directly from its own mining operations) raised $13.5m. The next auction of mined emeralds and beryl concludes on Friday.Gemfields shares had lost 1.27% to 48.50p at 14:39 on Thursday.DC