A Chinese research team has identified a common orange-yellow lichen as a potential field indicator for undiscovered rare earth element (REE) deposits, a finding that could reshape low-cost mineral prospecting worldwide. The study, published in the peer-reviewed journal Economic Geology on July 27, argues that the lichen's vivid colouration makes it a visible, ground-level clue to rare earth-bearing carbonatite rock beneath the surface.

The discovery and what it means

The research, titled 'Lichen as a Potential Exploration Tool for Rare Earth Element – Enriched Carbonatites', centres on Xanthoria elegans, a bright orange-yellow crustose lichen found on exposed rock surfaces across multiple climates. Scientists found the species accumulates rare earth elements from the underlying substrate, making its distinctive colour a surface-visible proxy for REE-enriched carbonatite formations below.

The team noted the lichen's colouration is easy to identify in the field, and said the discovery could be integrated with unmanned aerial vehicles (UAVs) and hyperspectral remote sensing technology to survey large, remote, or difficult terrain at scale — dramatically reducing the cost and time of traditional geological prospecting.

Why it matters for rare earth exploration

Rare earth elements are critical inputs for electric vehicle motors, wind turbines, defence electronics, and consumer devices. Identifying new deposits outside established supply chains has become a strategic priority for governments and mining companies globally. A low-cost biological indicator that can be cross-referenced with aerial imaging could accelerate that search considerably.

The research was conducted with involvement from Peking University and the Chinese Academy of Sciences, with fieldwork linked to the Bayan Obo mining area in Inner Mongolia — the world's largest known rare earth deposit — as well as sites in Xinjiang.

Historical context: a second biological indicator

Professor Li Yang of Peking University and the Chinese Academy of Sciences placed the finding in a long lineage of Chinese geobotanical research. Speaking on August 17, he said: 'This is the second time Chinese scientists have discovered a similar indicator – the first was copper grass in the 1950s – and both are original scientific discoveries in mineral exploration.'

Chinese scientists have pursued biological prospecting indicators for decades, and the copper grass precedent from the 1950s established a methodological tradition that this lichen study now extends to rare earths.

What's next

The researchers indicated that combining lichen mapping with UAV-mounted hyperspectral sensors could enable rapid screening of carbonatite-bearing regions across Africa, Central Asia, and other geologically prospective zones where ground access is limited. Mining companies and national geological surveys that adopt this dual biological-remote sensing approach could gain a meaningful edge in the global race to diversify rare earth supply chains.

The question now is whether international mining operators and government geological bodies will move quickly to validate and operationalise the method beyond China's existing deposit base.