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Preobrazhenskite mineral

Preobrazhenskite is the grandfathered magnesium borate species Mg3B11O15(OH)9 in the September 2026 IMA-CNMNC list. Its 1956 entry is an original-description year, not an approval identifier. Burns and Hawthorne refined a natural crystal from the Inder borate deposit, Kazakhstan, in orthorhombic Pbcn symmetry, with a = 16.291(4), b = 9.181(2) and c = 10.571(2) angstrom. Complex borate sheets parallel to (010) are linked through two octahedrally coordinated magnesium sites. Hydrogen positions were located from difference-Fourier maps; a crystallographically symmetric H site is an average structural model whose true local symmetry the authors explicitly left uncertain. Possible off-centre disorder and a high-temperature transition were suggestions, not experimentally demonstrated transformations. The study reported no new bulk chemical analysis or microbial experiment. This magnesium borate is distinct from potassium-bearing kaliborite, elemental boron and the borates commodity. No criticality designation, extraction mechanism or industrial recovery is inferred.

Sources & References

  1. ima_2026_09: IMA-CNMNC, The New IMA List of Minerals, September 2026: PDF page 177, Preobrazhenskite row; page 1, status/year definitions. Official list and current CNMNC landing page checked on 16 October 2026; status G, description year 1956.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-16)
  2. burns_hawthorne1994: Burns and Hawthorne (1994), Structure and hydrogen bonding in preobrazhenskite, a complex heteropolyhedral borate, Canadian Mineralogist 32, 387-396. Complete ten-page author-hosted original: natural specimen and refinement pp. 388-390, Tables 1-4, structure Figures 1-3 pp. 391-392, hydrogen-bond analysis Table 5 p. 390 and Figures 4-6 pp. 392-393, IR spectrum Figure 7 p. 394 and fitted-band Table 6/Figures 8-9 p. 395. Abstract and Table 1 use I >= 2.5 sigma(I) for observed reflections, whereas p. 388 prose prints the opposite inequality. The p. 394 OH(3) disorder discussion switches to H(6) labels in its final sentence. These inconsistencies are not silently repaired into a new atomic model. The five fitted IR components are not treated as five separately resolved measured peaks.
    https://www.frankhawthorne.com/_files/ugd/70a3a9_52f962a50804426ca437455347705cfe.pdf (accessed 2026-10-16)
  3. cod_9004294: Crystallography Open Database 9004294, live CIF retrieved 16 October 2026, revision 293658 dated 3 August 2024. The derivative of AMCSD 0005367 identifies the 1994 Burns-Hawthorne structure, formula B11 H9 Mg3 O24 and P b c n symmetry, with atomic and displacement-parameter loops. It is a structure accession rather than an IMA species-approval identifier. It does not supply the original measured reflections needed for independent re-refinement.
    https://www.crystallography.net/cod/9004294.cif (accessed 2026-10-16)

Curation History

Timestamp Curator Action Summary
2026-10-16T06:52:26.197274Z codex (GPT-6; codex) CREATE Created preobrazhenskite identity from current authority and natural-crystal evidence, preserving unresolved H-site interpretation without a speculative mechanism.
2026-10-16T07:03:51.879402Z codex (GPT-6; codex) EDIT Corrected primary-source figure and page locators after independent review finding F1 under issue 485; scientific claims remain unchanged.

Record source: data/records/preobrazhenskite.yaml