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Amblygonite mineral

Amblygonite is the fluorine-dominant lithium aluminium phosphate mineral with ideal formula LiAl(PO4)F, distinct from hydroxyl-dominant montebrasite and from lithium as an element. Natural crystals form a substituted F/OH series rather than necessarily pure endmembers. Groat2003 provides primary neutron-diffraction and NMR evidence for this series, including F-rich natural specimens. Triclinic P-1 and the centered C-1 convention describe settings of the same structure. A separate thesis reports heating of a natural specimen labelled amblygonite, but its mixed starting material and conflicting fluorine estimates straddle the species boundary. The thermal observation is retained only for that author-assigned specimen, not as a universal amblygonite decomposition threshold, microbial mechanism or lithium recovery yield.

Microbial & Biochemical Mechanisms (1)

Abiotic thermal breakdown of an author-assigned amblygonite-bearing specimen

other

In situ powder diffraction of the natural Nagatare specimen XN163 showed changes with heating, which the thesis interprets as partial breakdown at 600 degrees C and complete breakdown with berlinite formation at 700 degrees C. Composition and phase-mixture limitations prevent treating this as a controlled pure-endmember transformation. The companion montebrasite record reuses the same crystal-series and field-texture studies, not an independent thermal replicate.

Experimental Context & Analytical Limits:
Shirose thesis analytical methods (printed pages 13-14, PDF pages 20-21) and Section 5.2.4 (printed pages 32-33, PDF pages 39-40) used a RIGAKU Ultima IV diffractometer and measured XN163 in situ from 50 to 700 degrees C. Heating was 10 degrees C/min under vacuum, with a ten-minute hold at each target before measurement. Numerical vacuum pressure, sample mass, independent heating replicates, a matched unheated treatment control and a lithium/fluorine product balance are not reported. Starting material is a natural substituted phosphate with lacroixite, not a synthetic pure LiAlPO4F standard.
Curated Evidence Points:
Section 5.2.4 and Figures 17-18 (printed pages 32-33, PDF pages 39-40) support the source-specific qualitative thermal sequence. Figure 17 shows diffraction changes; the text assigns anhydrous phosphates at 600 degrees C and berlinite at 700 degrees C. No quantitative phase-refinement series, isolated berlinite yield, recovered lithium product or closed mass balance is presented. Approaching monoclinic cell geometry does not demonstrate isolation of the hypothetical high-temperature C2/c phase proposed in Section 5.3.
Table 1 (printed page 21, PDF page 28) assigns XN163 bulk-XRD F/(F+OH)=0.54, EPMA mean 0.47 with range 0.39-0.50, and 4.8(5) wt% lacroixite. Figure 17 labels F=0.54, whereas the Figure 18 legend labels the same specimen F=0.45. These estimates cross the F/OH species boundary and are not silently reconciled. EPMA Li2O and H2O are stoichiometrically calculated in Tables 2-3, not independent lithium and water assays. Thus the source name cannot establish a pure amblygonite feed.
Context_only Source: groat2003
Methods (pages 197-199), Table 2 (page 198), Table 11 (page 206) and Figures 1-15 establish natural-crystal structure and F/OH-related Li-site models. The AF-46 and Saxony specimens have neutron-derived F fractions 0.55 and 0.77; Table 11 reports differing composition estimates from other techniques. They are separate natural specimens from heated XN163. Split Li-site occupancies and NMR peak intensities are structural measurements or constrained models, not recoverable-lithium fractions. These data also ground cmmmech:montebrasite within the same study lineage.
Context_only Source: ima_2026_09
The exact Amblygonite row gives LiAl(PO4)F and grandfathered status, original-description year 1818. This verifies the mineral identity independently of the thesis specimen assignment and confers no criticality designation.
The complete entry gives LiAlPO4(F,OH), triclinic centered C-1 crystallography and substituted natural analyses. The ideal F endmember is distinct from an arbitrary commercial lithium-phosphate label or any mixture called amblygonite.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Amblygonite row, PDF page 9; page 1 defines grandfathered status and original-description year 1818, not an approval identifier.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15)
  2. handbook_amblygonite: Handbook of Mineralogy. Amblygonite, complete one-page identity, crystallography, chemistry and occurrence entry.
    https://handbookofmineralogy.org/pdfs/amblygonite.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/amblygonite.yaml