(IDEX Online) - Prices of rough rubies have more than doubled in the last two years, said Gemfields as it announced results of its latest sealed-bid auctions.The UK-based colored gems miner achieved an average $290 per carat earlier this month, compared to $132 in December 2021.Gemfields sold all 97 lots of mixed-quality rough rubies from the Montepuez mine, in Mozambique, in a series of seven online auctions after viewings in Bangkok.It offered and sold a total of 239,591 carats, realizing $69.5m. The previous auction, in June, achieved $80.4m at an average $266 per carat on sales of 302,317 carats.Adrian Banks, Gemfields' managing director of product & sales, said: "We've seen ruby prices at our auctions go from strength to strength in recent years and our final auction of 2023 has further endorsed that trend."This auction has shown that the demand and pricing for rough rubies is decidedly healthy. Gemfields' total auction revenue for 2023 stands at USD 242 million, the second highest in our history."Pic courtesy Gemfields