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Kozoite-(Nd) mineral

Kozoite-(Nd) is the neodymium-dominant orthorhombic rare-earth hydroxyl carbonate mineral with ideal formula Nd(CO3)(OH), approved as IMA 1998-063. It is distinct from elemental neodymium, kozoite-(La), hydroxylbastnäsite-(Nd) and commercial rare-earth feeds. The original Niikoba, Hizen-cho, Japan material consists of crystals smaller than 10 µm in an alkali olivine basalt cavity. Six-grain microprobe analyses show a mixed rare-earth composition, including Nd0.85 and La0.61 on a two-cation basis, rather than a pure Nd end member. Fluorine was not detected; no detection limit is supplied. Carbon and hydrogen were measured separately by triplicate elemental analysis using approximately 5 mg portions. Synchrotron powder diffraction and Rietveld refinement give Pmcn, a = 4.9829(1), b = 8.5188(2), c = 7.2570(2) Å and Z = 4. Hydrogen positions were not located, and the original study could not exclude a nearly orthorhombic monoclinic structure without suitable single crystals. The thermal experiment below concerns this natural mixed-REE material, not an isolated synthetic Nd end member. These sources do not establish microbial formation, industrial recovery or a jurisdiction-specific criticality designation.

Identifiers & Classification

System Identifier Label
IMA IMA:1998-063 Kozoite-(Nd)

Microbial & Biochemical Mechanisms (1)

Abiotic thermal dehydration and decarbonation of natural kozoite-(Nd)

other

Heating natural mixed-REE kozoite-(Nd) produced two endothermic mass-loss events. At the first peak, 485 °C, thermogravimetry measured 16.07 wt% loss and simultaneous gas chromatography-mass spectrometry detected CO2 and H2O. The authors attribute 11.98 wt% to CO2 and 4.09 wt% to H2O from the gas-analysis results. At the second peak, 716 °C, the mass loss was 9.89 wt% and only CO2 was detected. The observations support dehydration and decarbonation under the stated heating conditions. Heated-residue phases were not identified, so no particular Nd oxide product, isolated-metal recovery or final-product purity is established.

Experimental Context & Analytical Limits:
Miyawaki et al. (2000) used a Rigaku TG-DTA/GC-MS analyzer in helium, heating from room temperature to 900 °C at 20 °C/min with simultaneous analysis of the exhaust gas. The thermal aliquot mass, helium flow, replication and measurement uncertainty are not specified; the approximately 5 mg portions described elsewhere belong to elemental analysis and are not assigned to this thermal run. The two events are within one heating experiment, not independent replicated treatments. Estimated total evolved CO2 and H2O were 21.87 and 4.09 wt%, respectively, whereas the separate elemental analysis in Table 1 gives CO2-equivalent 21.10 wt% and H2O-equivalent 5.44 wt%. Although the source calls these results comparable, their differences and unspecified uncertainties are retained here. No microorganisms, solution extraction assay, separated metal product or industrial-scale operation was involved.
Curated Evidence Points:
Thermal methods and first-event results on page 1077, continuation on page 1079, and Figure 5 on page 1080 establish the helium atmosphere, heating rate, two endotherms, corresponding losses and evolved-gas identities. Table 1 supplies the distinct elemental-analysis estimates; these are not substituted for thermogravimetric measurements. The record preserves the natural mixed-REE substrate and does not infer an unmeasured residue phase, recovery yield or microbial mechanism.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Definitions PDF page 1 and Kozoite-(Nd) row page 116: Nd(CO3)(OH), A, 1998-063, Japan. Official homepage and downloaded authority list checked 16 October 2026.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-16)
  2. miyawaki2000: Miyawaki R, Matsubara S, Yokoyama K, Takeuchi K, Terada Y and Nakai I (2000). Kozoite-(Nd), Nd(CO3)(OH), a new mineral in an alkali olivine basalt from Hizen-cho, Saga Prefecture, Japan. American Mineralogist 85:1076-1081. DOI 10.2138/am-2000-0724. Complete six-page original, Tables 1-4 and Figures 1-6 inspected. Chemistry pages 1076-1077 and Table 1; powder structure pages 1077-1079; thermal methods/results pages 1077 and 1079 and Figure 5 page 1080. Crossref and publisher metadata confirm 2000 publication, separately from later online posting.
    https://doi.org/10.2138/am-2000-0724 (accessed 2026-10-16)

Curation History

Timestamp Curator Action Summary
2026-10-16T02:42:30.560325Z codex (GPT-6; codex) CREATE Added verified mineral identity and bounded abiotic transformation evidence, preserving natural/synthetic boundaries, measured versus calculated values, source discrepancies and missing experimental details.

Record source: data/records/kozoite-nd.yaml