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Zincite mineral

Zincite is the hexagonal ZnO mineral species listed by IMA-CNMNC in September 2026 with grandfathered status G and original-description year 1845, not a numbered approval. The Handbook documents natural Zn-dominant oxide with possible Mn substitution. This owner is distinct from elemental zinc, hydrozincite, zinc oxalate and mixed zinc-bearing wastes. Evidence below concerns commercial zincite-structured ZnO in fungal experiments and a separate source-described natural zincite specimen in an abiotic dissolution experiment. Commercial particles are synthetic analogues, not natural ore. No criticality designation, phase-specific recovery yield or industrial deployment is asserted.

Microbial & Biochemical Mechanisms (2)

Partial transformation of zincite-structured nanoparticles by fungal-conditioned liquid

biomineralization Microbial

Associated Organisms: Aspergillus niger (NCBITaxon:5061)

Liquid conditioned by Aspergillus niger CBS 140837 transformed part of a commercial ZnO nanoparticle preparation into a zinc oxalate dihydrate-assigned phase while residual zincite remained. The fungus conditioned the liquid upstream; live-cell contact during the nanoparticle reaction was not demonstrated. Dissolution followed by oxalate precipitation is consistent with the observations, but the specific ligand requirement and proposed core-shell architecture were not established by matched controls or spatial phase mapping.

Experimental Context & Analytical Limits:
Sebesta et al. Sections 2.2-2.4 describe seven-day static fungal growth in Sabouraud medium at 25 degrees C in darkness, then transfer of harvested mycelium into 50 mL sterilized distilled water for three days. After biomass removal and 0.45 micrometre filtration, 47.5 mL conditioned liquid was combined with 2.5 mL commercial ZnO dispersion, reported as 500 mg ZnO nanoparticles, and reacted statically for five days. Reaction temperature, independent replication, drying temperature and post-filtration sterility were not separately established for this arm. The decanted white solid was dried for XRD/TEM. No time-matched unconditioned-water, pH-matched or pure-oxalate comparison is reported for this phase experiment. It is separate from the seven-day live-culture assay nominally dosed at 6.5 mg Zn/L and is not a soil or ore-leaching test.
Curated Evidence Points:
Section 2.4 and Figure 4 explicitly compare starting bulk ZnO, starting nanoparticles and the five-day product with zincite and zinc oxalate dihydrate references. The product contains both assigned phases. Section 3.2 and Figure 5 show particles without a substantial size change, supporting partial conversion rather than a phase-pure isolated product. The proposed surface oxalate layer in Section 4.2 remains a hypothesis.
Section 3.2 reports oxalic acid falling from 11.6 to 1.2 mmol/L and estimates about 43 mg, or 8.6% of the stated 500 mg ZnO, transformed. This is not a measured quantitative XRD fraction or recovered-product yield; no complete Zn/oxalate mass balance or control for other oxalate losses is supplied. The experiment establishes the narrower mixed-phase observation, not a verified conversion efficiency.
The separate live-culture comparison in Sections 2.1-2.2 and 3.1, Figures 1-3, reports six replicates and a no-added-Zn inoculated control, not a sterile ZnO control. The stated common dose of 6.5 mg Zn/L conflicts with 0.0033 g bulk ZnO in 50 mL (about 53 mg Zn/L by formula-based calculation). Figure 2c also plots dissolved Zn concentrations above the stated initial 6.5 mg/L. These unresolved quantities prevent adopting the reported uptake percentage or cross-form mass balance here. Ultrafiltrate below 3 kDa is an operational fraction, not proof of free Zn2+ speciation. SI Table S1/Figure S1 concern a separate ionic-Zn preliminary toxicity experiment, not nanoparticle yield.

Chemical dissolution of a source-described zincite specimen

other

Ground zincite was dissolved with thiophenol and 1-methylimidazole in acetonitrile to give an optically clear solution whose proton NMR was assigned to Zn(SPh)2(MeIm)2. This is a laboratory chemical dissolution route; it does not establish microbial activity or a quantified recovered zinc product.

Experimental Context & Analytical Limits:
Koskela et al. describe an orange specimen obtained from a private seller as natural zincite mined in Poland. Its geological provenance was not independently authenticated; the phase assignment is supported by powder XRD after mortar-and-pestle grinding. The zincite subsection reports dissolution at 75 degrees C for 24 h. ESI Figure S31 specifies MeIm at three equivalents and thiophenol at 2.4 equivalents in acetonitrile-d3. The main methods use nitrogen-protected, degassed reactions. The mineral arm does not separately tabulate feed mass, replicate count or a gravimetric dissolution balance. Synthetic-powder kinetics are not transferred quantitatively to this specimen.
Curated Evidence Points:
Zincite mineral dissolution and ESI Figures S29-S31 show wurtzite-structured ZnO diffraction, before/after solution appearance and the assigned molecular solute spectrum. Optical clarity and solution NMR support dissolution and solute identity within detection limits, not an independently measured 100% extraction yield or absence of every minor impurity.
Identification of molecular solute reports that the separate synthetic ZnO powder did not dissolve with either ligand alone. These controls and the modeled surface pathway inform chemical interpretation but are not mineral-specific rate measurements. The thermal decomposition section concerns isolated complex crystals, so its ZnS residue is not assigned as a measured downstream yield from the natural-specimen arm. No biological organism is involved in this experiment.

Sources & References

  1. ima_2026_09: IMA-CNMNC, The New IMA List of Minerals, September 2026. Definitions PDF page 1 and Zincite row page 241: ZnO, G, 1845. Retained official original rechecked against current issuing-site listing.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15)
  2. handbook_zincite: Handbook of Mineralogy, Zincite, complete one-page version 1 datasheet, copyright 2001-2005; hexagonal structure, composition (Zn,Mn2+)O and natural occurrence.
    https://www.handbookofmineralogy.org/pdfs/zincite.pdf (accessed 2026-10-15)
  3. sebesta2020: Sebesta M et al. (2020). Fungus Aspergillus niger Processes Exogenous Zinc Nanoparticles into a Biogenic Oxalate Mineral. Journal of Fungi 6, 210. DOI 10.3390/jof6040210. Complete ten-page original, Figures 1-5 and official six-page supplement including Table S1/Figure S1.
    https://doi.org/10.3390/jof6040210 (accessed 2026-10-15)
  4. koskela2022: Koskela KM, Quiton SJ, Sharada SM, Williams TJ and Brutchey RL (2022). Kinetics and mechanistic details of bulk ZnO dissolution using a thiol-imidazole system. Chemical Science 13, 3208-3215. DOI 10.1039/D1SC06667F. Complete original text, NSF-deposited thirteen-page manuscript and official twenty-one-page ESI; natural zincite subsection and Figures S29-S31 are the curated specimen arm.
    https://doi.org/10.1039/D1SC06667F (accessed 2026-10-15)
  5. ncbi_niger: NCBI Taxonomy 5061, Aspergillus niger, species. Current taxonomy XML inspected; species identifier does not independently authenticate source strain CBS 140837.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=5061&mode=info (accessed 2026-10-15)

Curation History

Timestamp Curator Action Summary
2026-10-15T01:19:26.231993Z codex / GPT-6 CREATE Created the independently reviewable mineral record from verified primary sources and authorities, retaining experimental controls, identity boundaries and quantitative limitations without inherited criticality.

Record source: data/records/zincite.yaml