Smithsonite mineral
Smithsonite is the zinc carbonate mineral Zn(CO3), listed by IMA-CNMNC in September 2026 with grandfathered status G and original-description year 1832. That year is not a numbered mineral approval. The Handbook of Mineralogy describes it as a calcite-group mineral formed in oxidized zinc deposits, sometimes replacing carbonate rocks and constituting zinc ore. This mineral owner is distinct from elemental zinc, dissolved zinc chloride, hydrozincite and mixed oxidized zinc ore. The experiment below concerns a laboratory precipitate assigned to smithsonite after drying; it does not demonstrate microbial extraction from natural smithsonite ore. No criticality designation is inherited from zinc, and no isolated-product recovery or industrial deployment is asserted.
Microbial & Biochemical Mechanisms (1)
Culture-associated formation of a smithsonite-assigned precipitate
biomineralization
Microbial
Associated Organisms:
Sporosarcina pasteurii (NCBITaxon:1474)
A prepared bacterial cell suspension mixed with urea and zinc chloride solution produced a precipitate whose dried powder diffraction pattern was assigned to smithsonite. The source calls the organism Bacillus pasteurii, BNCC337394; the current species name is Sporosarcina pasteurii. Ureolysis-associated carbonate precipitation is the authors' interpretation. The observations support culture-associated formation of this prepared solid, but do not establish a cell-surface nucleation site, an enzyme-specific requirement, phase purity or the mineralogy of the wet precipitate.
Experimental Context & Analytical Limits:
The traditional tube assay mixed 5 mL of prepared bacterial suspension, 5 mL of urea solution and 10 mL of a separately prepared analytical-grade ZnCl2 solution simultaneously, with measurements after 24 h. The bacterial suspension had reported OD600 about 1.0 and urease activity 4-5 U/mL. Figure 1 depicts cultivation, centrifugation and washing. Detailed nutrient medium, cultivation and cell-preparation methods are delegated to Huang et al. (2024), DOI 10.1016/j.jenvman.2023.119868, whose full methods were not acquired here; those missing conditions are not reconstructed. The main article does not independently specify the physical assay temperature; its 30 degrees C setting applies to the geochemical model. Table 2 varies stated test Zn concentrations of 1, 2, 5 and 10 mmol/L and urea concentrations of 20, 50 and 100 mmol/L. These are retained as the authors' test concentrations without inferring stock-to-final dilution conversions. Triplicate specimens per case are reported. No matched uninoculated, killed-cell, no-urea or pH-matched chemical precipitation controls are documented in this experimental program. Separate Cd, Pb and Cu tests are not mixed-metal feed assays and are not incorporated as zinc observations. No independent authentication or sequence accession for the BNCC337394 stock was verified.
The traditional tube assay mixed 5 mL of prepared bacterial suspension, 5 mL of urea solution and 10 mL of a separately prepared analytical-grade ZnCl2 solution simultaneously, with measurements after 24 h. The bacterial suspension had reported OD600 about 1.0 and urease activity 4-5 U/mL. Figure 1 depicts cultivation, centrifugation and washing. Detailed nutrient medium, cultivation and cell-preparation methods are delegated to Huang et al. (2024), DOI 10.1016/j.jenvman.2023.119868, whose full methods were not acquired here; those missing conditions are not reconstructed. The main article does not independently specify the physical assay temperature; its 30 degrees C setting applies to the geochemical model. Table 2 varies stated test Zn concentrations of 1, 2, 5 and 10 mmol/L and urea concentrations of 20, 50 and 100 mmol/L. These are retained as the authors' test concentrations without inferring stock-to-final dilution conversions. Triplicate specimens per case are reported. No matched uninoculated, killed-cell, no-urea or pH-matched chemical precipitation controls are documented in this experimental program. Separate Cd, Pb and Cu tests are not mixed-metal feed assays and are not incorporated as zinc observations. No independent authentication or sequence accession for the BNCC337394 stock was verified.
Curated Evidence Points:
Support
Source:
huang2025
Section 2.2.1(3), Figure 2U and Section 3.2 identify the phase evidence specifically with the traditional assay at stated 10 mmol/L Zn and 100 mmol/L urea. The Zn pattern is compared with PDF 08-0449, ZnCO3, and the authors identify smithsonite. Samples were dried at 105 degrees C, ground, passed through a 0.1 mm sieve and kept dry at 40 degrees C. No wet-solid pattern or heating comparison is provided. This qualitative XRD assignment therefore concerns the prepared dry specimen; it is not a quantitative phase fraction, proof of an unchanged as-formed phase, or an isolated smithsonite yield.
Partial
Source:
huang2025
Figure 2M and Section 3.1.4 report lower 24 h Zn removal at higher initial Zn. At stated 100 mmol/L urea, removal falls from 99.89% at 1 mmol/L Zn to 40.67% at 10 mmol/L Zn. Equation 1 defines the percentage as initial minus remaining solution metal concentration divided by initial concentration, multiplied by 100; atomic absorption measures the metal and Nessler analysis measures ammonium as a ureolysis indicator. This endpoint depletion is not a kinetic rate or a mass yield of smithsonite. The supernatant separation cutoff and analytical detection limits are not specified in the inspected main paper. Ammonium and pH trends are compatible with inhibited ureolysis, but do not independently demonstrate molecular toxicity or bacterial viability. Figures 2N and 2P show model-versus-test disagreement, generally with larger simulated removal and pH. The Visual MINTEQ calculation uses measured ammonium and assumes carbonate at half that concentration; it is not an abiotic experimental control or an independent mineral assay.
Context_only
Source:
huang2025
The distinct sequential-addition assays in Figure 4D-F use stated 50 mmol/L urea and delay Zn addition by 0.5-8 h after mixing bacteria and urea, with total elapsed time fixed at 24 h from that initial mixing. The compared endpoints thus also differ in duration of Zn exposure; the horizontal axis is the pre-addition interval, not a Zn-depletion time course. Figure 4E supports improved solution removal, approaching complete removal in some cases after about 1-2 h of prior ureolysis. No corresponding sequential-assay XRD establishes that depleted Zn became smithsonite. Section 3.3 describes parameters increasing with delay, whereas the 10 mmol/L Zn curve in Figure 4E does not increase monotonically through 8 h. The delayed-addition results are consequently retained as assay context, not a uniform 100% result, demonstrated smithsonite production efficiency or industrial recovery.
Context_only
Source:
ncbi_pasteurii
Current NCBI taxonomy supports the mapping from the source's Bacillus pasteurii name to Sporosarcina pasteurii at species level. It does not establish the identity, purity or viability of the reported experimental culture or justify substituting a type-strain identifier for BNCC337394.
Sources & References
-
ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Definitions on PDF page 1 and Smithsonite row on page 201: Zn(CO3), G, 1832. Fresh issuing-site PDF inspected.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-12) -
handbook_smithsonite: Handbook of Mineralogy, Smithsonite, ZnCO3. Complete one-page original datasheet, version 1, copyright 2001-2005: occurrence and mineral-group context.
https://handbookofmineralogy.org/pdfs/smithsonite.pdf (accessed 2026-10-12) -
huang2025: Huang X, Zhang R and Zheng J (2025). Comparison of the efficiency of traditional MICP and two-step MICP method for immobilizing heavy metals in aquatic environments. Biogeotechnics 3, 100106. DOI 10.1016/j.bgtech.2024.100106. Complete official ten-page original, all four figures and two tables; online 25 May 2024, journal volume dated 2025. Methods pages 2-4, Zn results page 6, phase assignment Figure 2U and Section 3.2, sequential assays Figure 4 and Section 3.3. No separate supplement identified in the inspected article or official landing-page inventory.
https://doi.org/10.1016/j.bgtech.2024.100106 (accessed 2026-10-12) -
ncbi_pasteurii: NCBI Taxonomy, taxon 1474, Sporosarcina pasteurii, species; Bacillus pasteurii is a listed synonym. This species-level mapping does not authenticate the experimental BNCC337394 stock.
https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1474&mode=info (accessed 2026-10-12)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-12T13:24:04.643903Z |
codex (GPT-6; codex) | create | Added authority-grounded smithsonite and a qualified culture-associated dried-precipitate assignment from complete original evidence. Kept solution depletion, sequential-addition context and mineral yield distinct; preserved culture, preparation, control and access limits. |
Record source: data/records/smithsonite.yaml