The study, published today in the journal Nanoscale, unveils for the first time how fluocerite, a rare mineral, rapidly forms and transforms into bastnäsite. The occurrence and origin of fluocerite in natural deposits were not fully understood, making it challenging for earth scientists to study this mineral in natural samples.

Now, the Trinity team has revealed a new crystallisation route that produces extremely tiny, nanometric-sized minerals. Some of these elusive minerals are incredibly small, just a few billionths of a meter in size, making them very difficult to observe in natural samples.

Their research has essentially found that fluocerite can act as a "seed" to promote the rapid formation of bastnäsite.

Fluocerite and bastnasite as seen under microscope

This new knowledge not only advances scientific understanding but also has practical implications, potentially leading to more efficient and cost-effective methods for extracting rare earth elements (REEs), which are vital for a wide range of technologies, from smartphones to renewable energy solutions. This discovery is crucial for researchers who have struggled to understand the intricate factors and pathways involved in the formation of these tiny, nanometric minerals.

Dr. Luca Terribili, the first author of the research at Trinity, said: "Earth science researchers working with natural samples have found it extremely challenging to understand all the factors controlling the formation of bastnäsite, which is the main industrial source of rare earth elements, as well as the various potential pathways of its formation. Here, we have shown for the first time that fluocerite can turn into bastnäsite.

“This discovery has been made by following a completely different approach – we built synthetic bastnäsite rocks in the laboratory to mimic the same processes occurring in nature and studied them with powerful spectroscopic and microscopic techniques. This approach not only helped to clarify the complex natural processes at play but also paves the way for more efficient extraction of rare earth elements.”

Above: Dr Luca Terribili, lead author, and Prof. Juan Diego Rodriguez-Blanco, Principal Investigator of this study.

Prof. Juan Diego Rodriguez-Blanco, Principal Investigator at Trinity, added: "Our study highlights how these transformations can occur at relatively low temperatures and very quickly. These insights are crucial for developing better industrial methods for extracting rare earth elements. The reaction that turns fluocerite to bastnäsite may seem a slower process, taking between five hours and a month depending on temperature, but it is very rapid on geological timescales."

The research article can be read on the publisher's website. The research was supported by Science Foundation Ireland, Geological Survey of Ireland, and the Environmental Protection Agency under the SFI Frontiers for the Future Programme. The research was conducted at the Department of Geology at the School of Natural Sciences, Trinity. iCRAG (Irish Centre for Research in Applied Geosciences) is an SFI center dedicated to advancing geosciences research with a focus on sustainable resource management and environmental protection.