They have been recently used to highlight the potential for rare earth elements (REE) in the phosphate deposits at Siilinjärvi (Finland); work done as part of the FRAME project. Raman and cathodoluminescence spectroscopy give clues regarding enrichment in REE of apatite. A fast qualitative assessment of the latter can be deduced from the spectroscopic data. Laser-induced breakdown spectroscopy (LIBS) helps constraining the distribution of apatite and REE in the different lithotypes.
Decrée et al. (2020). Applied Geochemistry 123, 104778. https://doi.org/10.1016/j.apgeochem.2020.104778