CMMMech
CMMMech > Mineral > Montebrasite

Montebrasite mineral

Montebrasite is the hydroxyl-dominant lithium aluminium phosphate mineral with ideal formula LiAl(PO4)(OH), distinct from fluorine-dominant amblygonite. The September 2026 IMA list records grandfathered status and original-description year 1871. Groat2003 Methods (pages 197-199), Table 2 (page 198), Table 11 (page 206) and neutron/NMR figures establish the natural substituted series: the Dunton specimen has neutron-derived F/(F+OH)=0.04, whereas estimates for the near-boundary Tanco specimen differ by technique and are not treated as a pure endmember. Triclinic primitive P-1 and centered C-1 are alternative settings, not evidence for separate polymorphs. In the Shirose thesis, Figures 13-16 (printed pages 29-31, PDF pages 36-38) show co-oriented lacroixite patches and low-fluorine montebrasite in a natural host; Figure 12 (page 25, PDF page 32) shows secondary montebrasite veins without lacroixite. Section 5.3 and Figure 19 (pages 34-36) interpret an exsolution sequence, but do not reproduce that sequence by controlled synthesis. Figure 21 and Table 5 (pages 38 and 39) include gem-quality XS110 with no observed lacroixite, so the patch texture is not universal. Lithium and water in the thesis microprobe tables were calculated stoichiometrically. These are primary identity and natural-texture observations; no microbial mechanism, measured lithium extraction, isolated recovery yield or mineral criticality is asserted. The studies are also used in cmmmech:amblygonite and are not independent experiments for each owner; the ambiguous XN163 heating arm is not transferred here as a montebrasite-specific threshold.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Montebrasite row, PDF page 147; page 1 defines grandfathered status and original-description year 1871, not an approval identifier.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15)
  2. handbook_montebrasite: Handbook of Mineralogy. Montebrasite, complete one-page identity, crystallography, chemistry and occurrence entry.
    https://handbookofmineralogy.org/pdfs/montebrasite.pdf (accessed 2026-10-15)
  3. groat2003: Groat LA, Chakoumakos BC, Brouwer DH, Hoffman CM, Fyfe CA, Morell H, Schultz AJ (2003). The amblygonite (LiAlPO4F)-montebrasite (LiAlPO4OH) solid solution: A combined powder and single-crystal neutron diffraction and solid-state 6Li MAS, CP MAS, and REDOR NMR study. American Mineralogist 88:195-210. Complete sixteen-page original, Tables 1-12 and Figures 1-15.
    https://doi.org/10.2138/am-2003-0123 (accessed 2026-10-15)
  4. shirose_thesis: Shirose Y. Mineralogical study of Li pegmatite from Nagatare, Fukuoka Prefecture, Japan: microtextures formed by exsolution and hydrothermal alteration. Kyushu University doctoral thesis, repository metadata 2015, title page March 2016. Complete 104-page repository PDF acquired; accepted scope is analytical methods, printed pages 13-14, and Chapter 5, pages 18-42, Figures 11-23 and Tables 1-5. The later 2018 journal version DOI10.2138/am-2018-6049 was not acquired and is not an independent experiment.
    https://doi.org/10.15017/1654660 (accessed 2026-10-15)

Curation History

Timestamp Curator Action Summary
2026-10-15T11:39:13.522857Z codex (GPT-6; codex) CREATE Added primary-supported mineral identity and narrowly qualified natural-sample evidence, preserving F/OH species boundaries, shared study lineage and source limitations without inherited criticality or microbial claims.

Record source: data/records/montebrasite.yaml