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Lanthanite-(La) mineral

Lanthanite-(La) is the lanthanum-dominant lanthanite mineral, with ideal formula La2(CO3)3(H2O)6·2H2O, equivalently La2(CO3)3·8H2O. The September 2026 IMA list treats it as a renamed species, with year 1987 s.p.; this nomenclatural action is not a unique mineral approval number. It is distinct from elemental lanthanum, the lanthanite group, other carbonate hydrates and commercial rare-earth feeds. Historical locality labels require caution: the IMA row retains Sweden, whereas Atencio et al. (1989) found their Bastnäs specimen B10531 to be Ce-dominant. Their reassessment of published Curitiba analyses includes La-dominant and Nd-dominant specimens, so neither all Bastnäs material nor all Curitiba material can be assigned to this species solely from its locality. The experiment below concerns a separately synthesized La carbonate analogue of lanthanite, not dissolution of a natural mixed-REE specimen. No jurisdiction-specific criticality designation, microbial process or industrial deployment is established by these sources.

Microbial & Biochemical Mechanisms (1)

Abiotic dehydration and partial rehydration of synthetic La lanthanite

other

Synthetic La lanthanite heated at 80 °C changed to a phase identified by powder X-ray diffraction as La tengerite-type carbonate after 7 h. When this product was placed in water at 21 °C, lanthanite reappeared. Figure 12 reports 89 wt% lanthanite and 11 wt% tengerite-type phase at 120.5 h, establishing partial return at that sampled endpoint. These are fitted crystalline phase fractions, not lanthanum extraction yields or recovery efficiencies. The experimental tengerite-type product is not assigned a natural La-dominant mineral-species identifier.

Experimental Context & Analytical Limits:
Laboratory abiotic experiment in Terribili et al. (2025). Initial lanthanite was synthesized by homogeneous mixing at 21 °C; synthesis scale and number of batches for this thermal sample are not specified. A 2 g portion of the resulting solid was heated in a lidded 50 mL porcelain crucible at 80 °C; 0.2 g samples were collected for XRD. A 0.3 g portion of the dehydration product was placed in a 15 mL glass reactor filled with Milli-Q water and left static at 21 °C; 15 mL is the stated reactor capacity, not an independently specified water volume. The initial phase and successive time points provide phase controls. Replicate numbers and uncertainty for this separate dehydration/rehydration arm are not specified. The text's broad statement about eventual transformation of all tengerite is not demonstrated by the final plotted sample, which still contains tengerite; Table SI-1 also lists both phases at 120.5 h. SEM changes and diffraction support a hydration-dependent structural change, while comparable forward/reverse activation energies and the proposed surface-energy explanation remain hypotheses. No microorganisms, natural ore feed, isolated-metal product or industrial-scale test was involved.
Curated Evidence Points:
Methods page 948 establishes the separate dry-heating and water-rehydration arms. Figure 10 shows lanthanite at 0 h, mixed phases at 5.5 h and tengerite-type material at 7 h; Figure 12 shows increasing lanthanite from 2 wt% at 5 h to 89 wt% at 120.5 h, with 11 wt% tengerite remaining. Figures 11 and 13 provide corresponding microscopy and SI Table SI-1 preserves separate crystallite-size estimates for both phases. The narrower observed phase change is supported; full return by 120.5 h, a measured thermodynamic equilibrium and a recovery yield are not asserted.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Definitions PDF page 1 and Lanthanite-(La) row page 121: La2(CO3)3(H2O)6·2H2O; Rn; 1987 s.p.; Sweden. Official homepage and downloaded list checked 16 October 2026.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-16)
  2. atencio1989: Atencio D, Bevins RE, Fleischer M, Williams CT and Williams PA (1989). Revision of the lanthanite group and new data for specimens from Bastnäs, Sweden, and Bethlehem, USA. Mineralogical Magazine 53:639-642. DOI 10.1180/minmag.1989.053.373.17. Complete four-page original, Table 1 and Figure 1 inspected. Bastnäs B10531 is Ce-dominant; Curitiba literature analyses span La/Nd dominance. Probe damage limits and the distinction between new analyses and compiled data are retained; publication year is 1989, not the later portal date.
    https://doi.org/10.1180/minmag.1989.053.373.17 (accessed 2026-10-16)
  3. terribili2025: Terribili L, Szucs AM, Maddin M, Zubovic KP, Rateau R and Rodriguez-Blanco JD (2025). Mechanistic Insights into the Early-Stage Crystallization and Nanophase Formation of Metastable Light Rare-Earth Carbonates. Crystal Growth & Design 25:945-962. DOI 10.1021/acs.cgd.4c01168. Complete 18-page published article, Methods pages 946-948, Tables 1-5, Figures 1-14 and eight-page Supporting Information 10.1021/acs.cgd.4c01168.s001 inspected. La dry-heating and rehydration: Figures 10-13, pages 954-958, and SI Table SI-1. Figure 12 retains 11 wt% tengerite at 120.5 h.
    https://doi.org/10.1021/acs.cgd.4c01168 (accessed 2026-10-16)

Curation History

Timestamp Curator Action Summary
2026-10-16T01:33:37Z codex (GPT-6; codex) CREATE Added distinct mineral identity and bounded abiotic phase-transformation evidence, retaining natural/synthetic boundaries, source discrepancies and unsupported criticality/microbial claims absent.
2026-10-16T01:48:04.791374Z codex (GPT-6; codex) EDIT Addressed review finding round108-lanthanite-la-thermal-synthesis-scale and issue #434 by removing an unsupported link from the separate thermal sample to the general solution recipe; synthesis scale and batch count remain unspecified, while reported thermal outcomes are unchanged.

Record source: data/records/lanthanite-la.yaml