Gemfields reports up to 26% revenue share to African governments from ruby, emerald operations

Gemfields Group Limited, the Guernsey-incorporated coloured gemstone producer, has reported that up to 26% of revenue generated from its African mining operations was paid to host governments over the past decade, underscoring its fiscal contribution across key resource-rich markets.

The gemstone producer disclosed updated “G-Factor for Natural Resources” metrics for its flagship operations, Montepuez Ruby Mining and Kagem Mining Limited, showing 10-year averages of 26% and 17%, respectively, from 2016 to 2025.

Driving transparency in resource wealth
First introduced in 2021, the G-Factor measures the proportion of mining revenue paid to host governments through royalties, corporate taxes, and dividends, offering a benchmark for transparency in natural resource management.

Gemfields said the metric highlights how effectively resource companies convert extraction activities into tangible fiscal benefits for host nations, particularly across sectors such as mining, oil, gas, and forestry.

In Mozambique, Montepuez Ruby Mining paid 23% of its revenue to the government in 2025 alone, maintaining strong fiscal contributions despite lower premium ruby output and operational disruptions, including delayed auctions and illegal mining activity.

Operational headwinds impact Zambia’s output
At Kagem in Zambia, the one-year G-Factor fell to 6% in 2025, significantly below its long-term average, reflecting a temporary suspension of mining operations in early 2025 and the impact of a short-lived 15% export tax on precious gemstones.

Sean Gilbertson said the divergence in performance across operations illustrates how fiscal contributions can fluctuate based on market dynamics and regulatory changes, while expressing confidence that Zambia’s contribution levels will recover as operations stabilize.

Mining operations at Kagem have since resumed, with improving market conditions expected to support a rebound toward its historical contribution range of around 18%.

Strategic footprint across Africa
Gemfields, a leading global producer of colored gemstones, operates a portfolio of mining assets across Africa, including majority stakes in both Kagem and Montepuez, two of the world’s most significant emerald and ruby deposits.

The company’s structured auction platform and proprietary grading system have played a central role in formalizing the global colored gemstone market, while its transparency initiatives aim to set industry standards for accountability in resource extraction.

The latest disclosure reinforces Gemfields’ positioning as a key contributor to government revenues in Zambia and Mozambique, even as operational volatility and commodity cycles continue to shape earnings and fiscal flows across the sector.