Monazite-(Gd) mineral

Monazite-(Gd) is the gadolinium-dominant monazite species with ideal formula Gd(PO4), approved as IMA 2022-055. It is distinct from elemental gadolinium, mixed rare-earth ores and tetragonal xenotime-(Gd), which shares its ideal formula. Ondrejka et al. (2023) characterized natural microscopic domains from the Zimna Voda quartz vein near Prakovce, Slovakia, using wavelength-dispersive electron-microprobe analysis, Raman spectroscopy and selected-area electron diffraction of a focused ion-beam lamella. These observations support monoclinic P21/n symmetry. The six analyses in Table 2 average 22.84 wt% Gd2O3 and contain substantial Sm and Nd; this is mixed mineral composition, not pure GdPO4, a bulk ore grade or a recovered gadolinium yield. Single-crystal X-ray diffraction was not performed because of crystal size. The unit-cell dimensions emphasized in the abstract and Table 3 are estimates from weighted synthetic end-members; they differ from the less precise electron-diffraction measurements. Density was calculated, while hardness and several other physical properties could not be determined. The proposed hydrothermal enrichment explanation is a geological interpretation, not a controlled formation or extraction experiment. This characterization does not establish microbial production, recovery performance, industrial deployment or a jurisdiction-specific criticality designation.

Record source: data/records/monazite-gd.yaml