Sean Gilbertson
Rainmakers & Potstirrers

Sean Gilbertson

CEO: Gemfields Group

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‘We would very much like to add a proper sapphire deposit, but those don’t crop up every day’

COLOURED gemstones have avoided the price slump in the diamond market that compelled De Beers to cut supply. In happy contrast, emerald and ruby prices have grown at a compound rate of 13% and 17% respectively in three years. This should give Gemfields reason to smile, and perhaps a modicum of comfort, even after accepting that the quality and quantity of coloured gems can be variable.

For evidence of this market volatility, look no further than Gemfields’ emeralds auction in November which had to be postponed owing to sub-optimal quality and lower-than-expected volumes. Gilbertson says he’s not worried about these ups and downs as there are plenty of other risks to worry about. Illegal mining remains a problem in Mozambique where Gemfields operates its Montepuez ruby mine. Added to this is the nearby insurgency that flares up from time to time. In 2022, Gemfields evacuated the mine and then in the following year suspended exploration at its Nairoto site. For all this, Gilbertson is undeterred. He can lean on the fact that his company survived the Covid pandemic which almost bankrupted it.

For the year ahead, Gemfields will spend $70m building a second processing plant at Montepuez which represents its largest capital outlay to date and will treble the mine’s processing capacity. The plant, which should come on stream in the first half of 2025, will be funded from a combination of cash and debt. On the merger and acquisition front, Gilbertson says Gemfields already owns the world’s biggest ruby and emerald mines, but would “certainly be there” if a world-class sapphire mine was up for sale.


As a director of Pallinghurst Resources, which was Gemfields’ largest single shareholder for many years, Gilbertson led Gemfields’ strategy in coloured gemstones from 2006 to 2017. He was appointed CEO in 2017 when Pallinghurst unbundled its stake. He studied mining engineering at Wits University, and spent time working in South Africa’s deep-level gold and platinum mines. He has also been a trader and worked in project finance. Sean is a keen cyclist, loves the bush, and is the legal custodian of seven critically endangered black rhino in Namibia.

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