Gemfields Group Ltd shares lost some lustre as it warned net profits for the half year to June dropped by more than two-thirds.
In a statement, the ruby and emerald producer said it is "reasonably certain" that its net profit after tax will be US$18.1 million for the six months ended 30 June 2023 against US$56.7 million a year ago.
Revenues fell at its key mines, Kagem and MRM, though emerald and mixed-quality ruby auctions saw robust demand for coloured gemstones while June's higher-quality emerald auction set a new record for any Kagem auction.
Fabergé revenues also fell to of US$8.4 million, while weak platinum company valuations saw a US$13.3 million write-down at Sedibelo.
Shares fell 1.5p or 10% to 13.25p.