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Szaibélyite mineral

Szaibélyite is the MgBO2(OH) mineral species in the September 2026 IMA-CNMNC list, with grandfathered status G and original-description year 1862 rather than a sequential approval number. The doubled structural formula Mg2(OH)[B2O4(OH)] describes the same ideal composition; it contains hydroxyl rather than required molecular water. Marincea characterized natural material from the Romanian type locality, Băița Bihor, whereas Grice refined a separate natural Penobsquis, New Brunswick, crystal in monoclinic P21/a with two hydrogen positions. Grice's boron and water quantities were ideal calculated values, not directly measured assays; the reported analytical total exceeds 100%. Szaibélyite is distinct from the manganese-dominant sussexite species, synthetic magnesium-borate products, elemental boron and the borates commodity. No criticality, microbial mechanism or industrial performance is inherited.

Microbial & Biochemical Mechanisms (1)

Thermal water loss and breakdown of natural szaibélyite separates

other

Heating characterized natural separates produced gradual water loss followed by a larger dehydroxylation event and a diffraction-assigned monoclinic Mg2B2O5 breakdown product. The specimens, atmosphere and source protocol ambiguities limit transfer of temperatures or mass losses to pure szaibélyite or other processing conditions.

Experimental Context & Analytical Limits:
Marincea sampled the Bolfu-Tony, Baia Roșie and Antoniu areas at Băița Bihor. Hand picking and magnetic/heavy-liquid separation were followed by pulverization and a one-day wash with cold 0.5 N HCl. The resulting separates were reported as at least 90% pure, with residual serpentine-group mineral detected by X-ray diffraction. Parallel TGA/DTG/DTA measurements used static air at 10 degrees C/min. A separate TGA/DSC apparatus used nitrogen at 30 mL/min with evolved-gas infrared analysis. The Methods give that arm a heating rate of 10 degrees C/min, but Table 7 footnote 2 says 20 degrees C/min; this remains unresolved. The earlier thesis Table 30 repeats the same specimen rows but identifies the DSC atmosphere as argon rather than nitrogen, also at 20 degrees C/min. Methods also describe 1 h at 20 degrees C under 10^-4 torr before analysis, whereas the thermal Results describe 12 h at 110 degrees C, without an explicit reconciliation by aliquot. No microorganisms were used.
Curated Evidence Points:
Pages 121-122, Figure 4 and Table 7 show preliminary mass loss between approximately 150 and 600 degrees C and a larger water-evolution event near 600-700 degrees C. In the illustrated sample 1672, the DTA and DTG peaks occur at 660 and 640 degrees C, respectively. The Table 7 air-DTA peak temperatures across five separately identified specimens range from 655 to 670 degrees C; these are different specimens, not five replicate measurements of one material. The source reports diffraction assigned to monoclinic P21/a Mg2B2O5 for the breakdown product, with unit-cell refinements in Table 8. These measurements support abiotic thermal conversion, not isolated boron recovery or a product-purity yield.
Article pp. 121-122 describe diffraction lines that weakened and broadened after approximately 300 degrees C but remained recognizable to 650 degrees C, with residual original-cell features at least to 700 degrees C. The temperature-resolved arm traced in the thesis is from Cacova Ierii and is not assigned here to Băița Bihor. The article's different descriptions of completion at 650-680 or 650-700 degrees C therefore must not be collapsed to a sharp universal threshold. Total mass losses include the earlier event and are not equivalent to the main-event loss or to the ideal hydroxyl content of a pure mineral. Residual serpentine and the ambiguous pretreatment and nitrogen heating rate constrain quantitative attribution. Fluorine in evolved gas was below the approximately 0.1 wt.% detection limit, not a measured zero.
Page 122 reports no separate 150-200-degree-C endothermic peak, contrasting with a cited earlier hydroxyl-ascharite result; the earlier experiment was not independently acquired here. Proposed assignment of early water loss to particular hydroxyl groups and slow structural accommodation is interpretive. No return to the starting szaibélyite, equal-duration unheated control, isolated-product mass balance or industrial operation was demonstrated.
The earlier thesis supplies the breakdown-product powder data referenced by the article: Table A.23 includes Băița Bihor specimen 1672 after heating in air to 900 degrees C, as specified on p. 245. It shares specimens and data with the 2001 article and is not an independent replication. Table 30 calls the DSC atmosphere argon at 20 degrees C/min, conflicting with the article's nitrogen descriptions; the exact atmosphere and rate cannot be reconciled from these texts. Table A.22 labels one specimen 1402 BB whereas Table 32 and the article use 1406; those labels are not silently equated. The temperature-resolved diffraction and cooled-product persistence in Figure 46 concern specimen 1821 from Cacova Ierii, a separate locality, and are not transferred to the Băița Bihor specimens. Extra low-temperature peaks in an unwashed Mașca-Băișoara sample are attributed to residual boric acid, not treated as a contradiction from an identically prepared pure szaibélyite feed.
Context_only Source: grice2008
The separate Penobsquis refinement locates two hydrogen positions and supports the hydroxyl-bearing structural model. Twenty microprobe analyses of seven grains measured Mg, Fe and Mn, while B and H contents were supplied from ideal stoichiometry and the structural interpretation. It does not independently repeat the Romanian heating experiment or resolve its protocol discrepancies.

Sources & References

  1. ima_2026_09: IMA-CNMNC, The New IMA List of Minerals, September 2026: PDF page 210, Szaibélyite row; pages 1-2, status and original-description definitions.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15)
  2. marincea2001: Marincea (2001), New data on szaibelyite from the type locality, Băița Bihor, Romania, The Canadian Mineralogist 39, 111-127, DOI 10.2113/gscanmin.39.1.111. Original article, analytical procedures pp. 112-114, thermal results pp. 121-122, Tables 6-8 and Figures 4-5.
    https://www.rruff.net/doclib/cm/vol39/CM39_111.pdf (accessed 2026-10-15)
  3. marincea1998: Marincea (1998), Cristallochimie et propriétés physiques des borates magnésiens des skarns de la province banatitique de Roumanie, doctoral thesis, École Nationale Supérieure des Mines de Saint-Étienne, HAL tel-01027512v1. Methods p. 41, thermal chapter pp. 236-246, Tables 30-32, Figures 44-46 and Appendix Tables A.21-A.23, pp. 433-435. The relevant sections of the 498-page thesis were inspected.
    https://theses.hal.science/tel-01027512v1/file/19980615-Marincea-S.pdf (accessed 2026-10-15)
  4. grice2008: Grice (2008), Szaibelyite: Crystal-structure analysis and hydrogen bonding, The Canadian Mineralogist 46, 671-677, DOI 10.3749/canmin.46.3.671. Natural Penobsquis specimen, microprobe and diffraction methods, Tables 1-3 and Figures 1-5.
    https://www.rruff.net/doclib/cm/vol46/CM46_671.pdf (accessed 2026-10-15)

Curation History

Timestamp Curator Action Summary
2026-10-15T21:20:37.456882Z codex (GPT-6; codex) CREATE Created a distinct szaibélyite species record with natural structure and abiotic thermal breakdown, retaining specimen impurities and conflicting thesis/article protocols.

Record source: data/records/szaibelyite.yaml