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Inderite mineral

Inderite is the Mg[B3O3(OH)5](H2O)4·H2O mineral species in the September 2026 IMA-CNMNC list, with status A and year notation 1962 s.p. for a special procedure, not a fabricated sequential approval identifier. It is distinct from its dimorph kurnakovite, from inderborite, elemental boron and the borates commodity. Gatta et al. studied natural Kramer Deposit, California, material by EPMA-WDS, laser-ablation mass spectrometry and neutron diffraction. The P21/c structure comprises borate-ring/Mg-polyhedron clusters connected by hydrogen bonds, with four Mg-bound water molecules and one interstitial water per formula unit. The chemical characterization is specimen specific, including modest electron-beam damage and an assumed B/H stoichiometry in the EPMA formula; it is not a resource-grade survey. Commodity criticality and microbial activity are not inherited.

Microbial & Biochemical Mechanisms (1)

Reconstructive pressure-induced transition in natural inderite

other

Single-crystal diffraction detected a transition from the ambient P21/c structure to the P21/n structure labelled inderite-II by the authors. They solved and refined the high-pressure structure and interpreted a boron coordination increase from three to four oxygen neighbours. The experimental label does not establish a separately approved natural mineral species. Recovery of the starting phase upon decompression is observed in this experiment; it does not establish a reversible industrial processing cycle.

Experimental Context & Analytical Limits:
A single approximately 20 x 15 x 10 micrometre crystal from the Borax open-pit mine, Boron, California, was compressed in a membrane-driven diamond-anvil cell at ESRF ID15b using helium and ruby pressure calibration with uncertainty of 0.05 GPa. Table 1 reaches 17.04(5) GPa and includes three decompression points. The inspected methods do not specify a calibrated sample-temperature series. The separate 2024 neutron measurements at 280 and 10 K are not high-pressure measurements on this crystal. No organism, extraction yield, recovered boron product or concrete performance was measured by this pressure experiment.
Curated Evidence Points:
Accepted-manuscript Table 1 and sections 4.1, 4.3 and 5 put the last low-pressure point at 6.15(5) GPa and first high-pressure point at 6.45(5) GPa. Figure 3 identifies the high-pressure diffraction pattern at 6.45(5) GPa. The authors report an approximately 7% discontinuity after dividing the doubled high-pressure cell volume by two for comparison. Table 1 retains the high-pressure cell at 5.43(5) GPa during decompression and recovers the starting cell at ambient pressure; it does not locate a precise reverse-transition pressure. Table 2 reports fitted bulk moduli of 26.5(7) and 41(5) GPa, respectively, using third-order Birch-Murnaghan fits.
The abstract and section 3.1 instead give a 6.45-6.94 GPa transition interval, while also identifying the high-pressure cell at 6.45 GPa. The manuscript abstract gives 37(4) GPa for the high-pressure bulk modulus, conflicting with Table 2 and results at 41(5) GPa. Its section 4.3 mentions 17.41(5) GPa, beyond the last Table 1 point. These discrepancies remain unresolved; the tables are identified explicitly rather than silently harmonized into one precise threshold or maximum. Hydrogen sites were absent from the starting refinement model, and unavailable pressure CIFs/SI limit verification of detailed water-site assignments and bond-length changes. The reported coordination interpretation is not a directly tracked hydrogen mechanism or an oxidation-state change of boron.
Context_only Source: gatta2024
Neutron methods and Tables 2-5 independently characterize the ambient-pressure structure at 280 and 10 K, locating fifteen independent hydrogen sites. A two-position O9w model with occupancies 0.60(10) and 0.40(10) was supported at 280 K but not at 10 K. Its cause remains unclear, with absorption correction limitations noted on p. 10. This is not independent replication of the pressure transition. Page 16 repeats the disputed 6.45-6.94 GPa interval; its contextual summary does not resolve the original paper's internal disagreement.

Sources & References

  1. ima_2026_09: IMA-CNMNC, The New IMA List of Minerals, September 2026: PDF page 101, Inderite row; pages 1-2, status and special-procedure definitions.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15)
  2. gatta2024: Gatta, Capelli, Comboni and Cannaò (2024), On the crystal-chemistry of inderite, Mg[B3O3(OH)5](H2O)4·H2O, Physics and Chemistry of Minerals 51, 21, DOI 10.1007/s00269-024-01281-w. Complete 18-page publisher PDF acquired from the German National Library: methods pp. 2-4; Tables 1-5; Figures 1-2; discussion pp. 9-17.
    https://d-nb.info/1342532252/34 (accessed 2026-10-15)
  3. gatta2024_cif: Gatta et al. (2024), original publisher supplementary CIF with 280-K unsplit, 280-K split-site and 10-K neutron models. The data-block labels say inderborite, but the mineral-name fields, MgB3H15O13 formula, cells and P21/c symmetry identify inderite. The file contains a malformed Mg atom-type token; it is not represented here as a validated machine-ready dataset.
    https://media.springernature.com/original/springer-static/esm/art%3A10.1007%2Fs00269-024-01281-w/MediaObjects/269_2024_1281_MOESM1_ESM.cif (accessed 2026-10-15)
  4. comboni2023: Comboni et al. (2023), On the anomalous high-pressure phase transition of inderite, MgB3O3(OH)5·5H2O, Solid State Sciences 140, 107187, DOI 10.1016/j.solidstatesciences.2023.107187. Inspected institutional accepted manuscript labelled Revision_1, 25 pages: methods pp. 5-11; Tables 1-2 pp. 7-8 and 13; Figures 1-5 and embedded Figure S1; results pp. 14-21. Publisher full text, separate Tables S1-S2 and pressure CIFs were not acquired.
    https://air.unimi.it/retrieve/6d06b12a-4745-4081-b216-108bcab61556/Inderite_Post-Print.pdf (accessed 2026-10-15)

Curation History

Timestamp Curator Action Summary
2026-10-15T23:03:46.714906Z codex (GPT-6; codex) CREATE Created a distinct inderite mineral owner with natural-specimen neutron identity and a bounded abiotic pressure transition, retaining manuscript pressure and modulus conflicts, recovery limits and unavailable pressure deposits.

Record source: data/records/inderite.yaml