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Childrenite mineral

Childrenite is the Fe2+-dominant aluminium phosphate mineral with ideal formula Fe2+Al(PO4)(OH)2(H2O), distinct from the Mn2+-dominant endmember eosphorite and oxidized related phases. The September 2026 IMA list records grandfathered status and original-description year 1823. Toupal et al. (2024) characterized two natural grains in granite collected on 11 July 2020 from two outcrops near the southern boundary of the Homolka granite, Czech Republic. Twenty electron-microprobe spots across those two grains gave Fe/(Fe+Mn) from 0.51 to 0.86; these are analytical spots, not twenty independent specimens. Single-crystal diffraction and Raman measurements on Grain A support an orthorhombic Cmca childrenite structure with divalent-cation bond valence at the mixed Fe site. This is specimen-specific structural evidence, not a direct oxidation-state assay of every natural childrenite. It improves on the older Handbook's Bba2 assignment and possible monoclinic interpretation without treating all historical specimens as identical. The crystals show patchy Fe/Mn zoning and probable uraninite inclusions; the inclusions are not independently confirmed as a uranium mineral here. Calculated water raises all microprobe totals above 100 wt%, which the authors attribute to beam-induced partial dehydration; this is not a controlled dehydration experiment. The chemical and structural observations distinguish the investigated grains from a merely compositionally similar ferric phase. The official CIF and main Table 2 disagree on temperature, 273(2) versus 293(2) K, and measured-reflection count, 5429 versus 5682; neither disputed value is adopted as a resolved condition. The CIF's Fe/Ca scattering-site model and formula-sum field are not treated as the measured Fe/Mn/Ca chemistry, and its analytical Si0.04 differs from the main formula's approximately Si0.01. These source limits do not remove the agreement on the unit cell, Cmca symmetry and the 602 observed reflections underlying R1=0.0295. This record establishes natural-mineral identity only, without an experimentally demonstrated formation, extraction, microbial transformation or recovery mechanism. No criticality designation is inherited from constituent elements.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Childrenite row, PDF page 43, Fe2+Al(PO4)(OH)2(H2O), G, 1823; status definitions page 1.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15)
  2. handbook_childrenite: Handbook of Mineralogy. Childrenite. Complete one-page entry; older Bba2 symmetry and possible monoclinic interpretation are qualified by the specimen-specific 2024 primary study.
    https://www.handbookofmineralogy.org/pdfs/childrenite.pdf (accessed 2026-10-15)
  3. toupal2024: Toupal J, Mauro D, Biagioni C, Zaccarini F, Giere R (2024). Structural and compositional data for childrenite from the Homolka granite, Czech Republic. European Journal of Mineralogy 36:1-10. Complete original; methods sections 3.1-3.5, Figures 1-6 and Tables 1-3. Table 1 is page 4, Tables 2-3 page 5; Figures 2-3 page 6, Figure 4 page 7, Figures 5-6 page 8.
    https://doi.org/10.5194/ejm-36-1-2024 (accessed 2026-10-15)
  4. toupal2024_si: Official three-member supplementary ZIP: Childrenite_Homolka.cif, Table S1.xlsx and one-page title sheet. The native workbook contains ten spots per grain, twenty total; CIF structural headers and atomic-site model inspected without independent re-refinement. Main/CIF temperature, reflection-count and analytical-formula differences remain unresolved.
    https://ejm.copernicus.org/articles/36/1/2024/ejm-36-1-2024-supplement.zip (accessed 2026-10-15)

Curation History

Timestamp Curator Action Summary
2026-10-15T13:56:06.161852Z codex (GPT-6; codex) CREATE Added a distinct mineral identity from primary evidence and authority checks, preserving natural versus synthetic material scope, source conflicts and limits; no microbial or inherited criticality claim.

Record source: data/records/childrenite.yaml