Gemfields Plc generated revenues of US$30.4 million from its auction of rough rubies held in Singapore, which returned an average realized price of US$27.79 per carat.

The company sold 1,094,406 carats, about 80% of the 1,372,145 carats offered, according to a Dec. 19 release.

The seven Montepuez auctions held since June 2014 have generated US$225.7 million in revenues.

Gemfields' ruby and corundum output jumped to 4.5 million carats in the third quarter this year, up from 500,000 carats in the same period of 2015, as a result of processing higher-grade, lower-value amphibolite resources.

The rubies are extracted by the company's 75%-owned Montepuez Ruby Mining from its Montepuez ruby deposit in Mozambique.