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Aristarainite mineral

Aristarainite is the approved sodium-magnesium borate mineral Na2Mg[B6O8(OH)4]2·4H2O, IMA1973-029, in the September 2026 IMA-CNMNC list. Hurlbut and Erd described natural crystals from the Tincalayu borax deposit, Salta, Argentina, including material separated from borax/kernite hosts with warm water. Their 1974 chemical analysis on 95.4 mg included potassium and yielded the historical oxide formula Na2O·MgO·6B2O3·10H2O. Ghose and Wan's 1977 single-crystal refinement revised that ideal hydration to eight oxide-formula waters, equivalent to the current structural formula. This revision came from the structural model, not a new bulk-water assay. Hexaborate units form chains parallel to b; magnesium and sodium link these into sheets parallel to (001), cross-linked by hydrogen bonds. One hydrogen on the O(14) water site was modeled as two half-occupied positions; this is crystallographic disorder, not a measured molecular-motion rate. The papers' qualitative water/acid solubility and proposed geological polymerization do not establish extraction kinetics or an engineered process. Species identity is distinct from the borates commodity and its constituent elements; no criticality, microbial mechanism or industrial recovery claim is inferred.

Identifiers & Classification

System Identifier Label
IMA IMA:1973-029 Aristarainite

Sources & References

  1. ima_2026_09: IMA-CNMNC, The New IMA List of Minerals, September 2026: PDF page 14, Aristarainite row, Na2Mg[B6O8(OH)4]2(H2O)4, status A, approval 1973-029; page 1, definitions. Current official landing page and linked dated list checked 16 October 2026.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-16)
  2. hurlbut_erd1974: Hurlbut and Erd (1974), Aristarainite, Na2O·MgO·6B2O3·10H2O, a new mineral from Salta, Argentina, American Mineralogist 59, 647-651. Complete five-page original: type material Harvard 109679 and occurrence pp. 647-648, Tables 1-3 p. 649, Table 5 chemistry p. 650, preparation and solubility statements p. 651, IR Figure 5 and Table 6 p. 651. The optical sign differs between the abstract and Table 4; neither is silently selected here. The historical ten-water formula is retained as an earlier interpretation, not substituted for the current accepted formula.
    https://msaweb.org/AmMin/AM59/AM59_647.pdf (accessed 2026-10-16)
  3. ghose_wan1977: Ghose and Wan (1977), Aristarainite: Na2Mg[B6O8(OH)4]2·4H2O: a sheet structure with chains of hexaborate polyanions, American Mineralogist 62, 979-989. Complete eleven-page original: hydration revision p. 979, natural Salta crystal and refinement p. 980, atomic sites Table 2 p. 981, hydrogen/disorder pp. 984-985, structural Figures 1-6 pp. 986-989. R=0.036 for 1941 reflections. Table 1's cell-content line prints OH2 inside its bracket, unlike the OH4 formula in the title and structural discussion; that line is not used to redefine the species. The publisher deposit AM-77-052 was acquired as a scanned supplement. The polymerization/paragenesis discussion is an interpretation, not a demonstrated heating or solution-conversion experiment.
    https://msaweb.org/AmMin/AM62/AM62_979.pdf (accessed 2026-10-16)
  4. ghose_wan1977_deposit: Publisher deposit AM-77-052 accompanying Ghose and Wan (1977), thirty-nine-page scanned file with the article first page, observed/calculated structure factors and refinement summaries. Table headers, representative rows and the final summary were visually inspected. No independent re-refinement or exhaustive numerical transcription of the deposited factors was performed.
    https://msaweb.org/MSA/AmMin/Supplemental_Data/Vol%2062%20p0979%20AM-77-052.pdf (accessed 2026-10-16)

Curation History

Timestamp Curator Action Summary
2026-10-16T08:05:07.925709Z codex (GPT-6; codex) CREATE Created aristarainite species identity with the 1977 structural hydration revision and explicit historical assay/model limits.
2026-10-16T08:10:56.892436Z codex (GPT-6; codex) EDIT Added the official scanned structure-factor deposit after acquisition; replaced the earlier access limitation without changing scientific claims.

Record source: data/records/aristarainite.yaml