JOHANNESBURG (miningweekly.com) – The inaugural auction of rough ruby and corundum mined at Aim-listed Gemfields’ 75%-owned Montepuez deposit, in Mozambique, has raised $33.5-million, taking the coloured-gemstones mining and marketing company’s overall revenue for rough gemstone sales to in excess of $143-million for the current financial year.

The auction, held in Singapore from June 12 to 17, had included both high- and low-quality ruby and corundum gemstones.

Of the 2.03-million carats on offer, 1.82-million carats were sold, with the auction yielding an average value of $18.43/ct.

Gemfields pointed out that its acquisition cost, capital expenditure and operating costs at the Montepuez deposit, to date, had totalled $34-million. The revenue from the first ruby auction had, therefore, nearly matched the aggregate expenditures at the mine.

“Since completing the acquisition of Montepuez – our first ruby deposit – in 2012, we have swiftly brought this greenfield asset into the operational and revenue-generating phases, producing over eight-million carats and simultaneously developing a first-of-a-kind, proprietary ruby grading system.

“The extension of our transparent and well-regarded auction platform into the ruby trade has been very well received by the market, with an expanded customer base now having access to reliably supplied and consistently graded rough emeralds, beryl, rubies and corundum,” Gemfields CEO Ian Harebottle said in a statement on Wednesday.

SP Angel commented in a note to clients that it was hopeful that the Montepuez mine should prove to be "immensely valuable".

However, it said this would depend on how many high-value stones are recovered. "It is possible that a handful of stones might have fetched the bulk of the value at this auction and it is the quantum of higher values achieved, combined with the discovery going forward of higher value stones, which will determine the value of this mine."

Gemfields would hold a second rough ruby and corundum auction before December 31.