Phytomining: A fern that makes rare earth elements!

Credit: Environmental Science & Technology (2025). DOI: 10.1021/acs.est.5c09617

Scientists have discovered a fern from South China that naturally forms tiny crystals containing rare earth elements (REEs). This breakthrough opens the door to a promising new way of "green mining" of these minerals called phytomining.

REEs are a group of 17 elements, all metals with similar properties that are essential for everything from wind turbines and electric car batteries to smartphones and medical scanners.

Extracting them is expensive and normally involves large-scale conventional mining operations that rely on harsh chemicals and cause significant pollution and land damage. That's why researchers are exploring cleaner, sustainable plant-based alternatives to collect REEs.

According to a paper published in the journal Environmental Science & Technology, the researchers studied the Blechnum orientale fern, which had been collected from REE-rich areas in South China. It was already known to be a hyperaccumulator, which is a plant that can grow in soil and water with high concentrations of metals and absorb them through its roots. But what they didn't know was the chemical form the REEs take when inside the plant. This knowledge is vital for designing the most efficient extraction process.

Using high-powered imaging technology and chemical analysis, the team discovered that the fern was forming nanoscale crystals of the REE-rich mineral monazite within its tissues, particularly in the cell walls and spaces between cells. Monazite is one of the main sources of rare earth elements in geological ore deposits worldwide.

The study authors also observed the crystal form, noting that it grows in a highly complex self-organizing pattern of tiny branches, likening it to a microscopic "chemical garden." This is the first time scientists have seen a living plant create a rare earth element crystal.

While we might not be going out to garden for REEs in the immediate future, the research is further proof that phytomining is feasible. The discovery, even with just one fern, strengthens the case that plants could one day provide a valuable, cheaper, and less destructive method for extracting much-needed rare earth elements.

Liuqing He et al, Discovery and Implications of a Nanoscale Rare Earth Mineral in a Hyperaccumulator Plant, Environmental Science & Technology (2025). DOI: 10.1021/acs.est.5c09617