Gemfields Group (AIM:GEM), the coloured gemstone miner listed on AIM and the JSE, said it is "reasonably certain" its net loss after tax for the six months to 30 June will reach $73.5 million, compared with a $20.5 million loss in the same period last year.
The blow stems largely from a $125.2 million non-cash impairment at Montepuez Ruby Mining (MRM), where premium ruby recoveries fell short of expectations during the period.
Total auction revenues rose to $102.8 million from $60.0 million a year earlier, with MRM contributing $76.1 million and Kagem $26.7 million, though Gemfields cautioned the comparison is distorted by a mixed-quality ruby auction deferred from December to February. Loss per share is expected at 4.3 US cents, against 1.7 cents a year earlier, while headline earnings per share is expected to turn positive at 0.6 cents, versus a headline loss of 1.5 cents in 2025's first half.
Gemfields also restated its 2025 full-year impairment upward, from $35.0 million to $65.0 million, after identifying a $30.0 million adjustment.
Interim chief executive David Lovett said the first half was "challenging", driven by the lower ruby recoveries, but pointed to early signs of improvement, with the PP2 plant now achieving and at times exceeding design throughput.
Kagem, he added, delivered "solid operational performance and good premium emerald recoveries" despite elevated costs.
Gemfields will publish full interim results on 30 September, followed by a shareholder webcast that morning.