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Argentojarosite mineral

Argentojarosite is the silver ferric hydroxysulfate mineral with ideal formula AgFe3(SO4)2(OH)6, with ferric iron. The September 2026 IMA list records it as redefined, 1987 s.p. It is distinct from potassium jarosite and from silver ions, metallic silver or a generic industrial jarosite precipitate. Mukherjee's 2013 Ohio State MSc thesis identified synthetic argentojarosite following silver-nitrate addition to an iron-oxidizing culture's ferric sulfate and poorly crystalline ferric precipitates. The thesis explicitly separates the biological iron-oxidation step from the subsequent abiotic precipitation step. Silver-bearing solids and relative diffraction crystallinity are not measures of silver recovery from an ore or waste, absolute product purity or microbial precipitation necessity. No constituent-element criticality is inherited.

Microbial & Biochemical Mechanisms (1)

Silver-driven precipitation after biological ferric-sulfate preparation

other Microbial

Associated Organisms: Acidithiobacillus ferrooxidans (NCBITaxon:920)

A composite mixed culture described as A. ferrooxidans oxidized ferrous sulfate before silver nitrate was added. Subsequent aging produced diffraction-assigned argentojarosite together with possible poorly crystalline residual ferric phases. Microbial involvement here denotes upstream iron oxidation in the combined two-stage route; Figure 5 labels the silver-addition stage abiotic, and the thesis leaves any direct bacterial contribution to precipitation unresolved.

Experimental Context & Analytical Limits:
Mukherjee2013 sections 2.1-2.2, printed pages 28-29: 100 mL cultures in 250 mL flasks at 22 plus/minus 2 degrees C and 180 rpm used 120 mM FeSO4.7H2O, 1.9 mM MgSO4.7H2O and 4.0 mM H2SO4, with phosphate supplied as 3.6 mM H3PO4 and nitrogen as 7.6 mM HNO3 instead of potassium and ammonium salts. The stock-culture method states 5% inoculum and pH 2.0 plus/minus 0.1; a separately measured modified-culture pH trajectory is not reported. AgNO3 supplied 0, 5, 20 or 40 mM Ag after the dark-red color was taken as evidence of completed Fe(II) oxidation at five to seven days. Products were sampled eight hours, five days or fourteen days after silver addition, centrifuged at 15000 g, washed twice with 1 mM H2SO4 and air-dried at room temperature for 72 hours. Cell viability after silver addition, accession-resolved community membership and independent replicate numbers were not established. Initial dissolved reagents are not an ore or waste feed.
Curated Evidence Points:
Sections 3.1-3.2, Figures 5-9 and Tables 7-10 (printed pages 30-40) identify argentojarosite from multiple powder-diffraction reflections matched to reference PDF2 41-1398, fitted cell parameters and elemental chemistry. Figure 8 shows its characteristic peaks at five, twenty and forty mM Ag after fourteen days, with no corresponding sharp phase pattern in the zero-Ag arm. The forty mM/fourteen-day sample had reported bulk Ag 18.42, Fe 28.99 and S 11.07 wt%, broadly near ideal composition; these are concentrations in the collected solids, not percentages of input silver recovered. The reference-card number identifies a diffraction reference and is not assigned as an external mineral identifier.
Sections 3.2 and 4, Figures 7-13 and Tables 7-10 do not quantify absolute phase purity or a silver mass balance. The zero-Ag phase is described as poorly crystalline and a possible schwertmannite precursor; assigning all starting solids to pure schwertmannite would overstate the diffraction. The more yellow and sharper-diffracting forty mM/fourteen-day product may still contain poorly crystalline ferric material. FWHM changes are peak-dependent, and several Table 7 reflections are narrower at twenty than forty mM, so a universal monotonic crystallinity rule is not inferred.
Sections 3.3-3.5 and Figures 14-16 (printed pages 45-51), with the separate Table 9 twenty mM row (printed page 40; PDF page 50), retain negative and abiotic comparisons. Separated culture solution produced insufficient precipitate for analysis within fourteen days; separated solid treated with twenty mM Ag showed no identified argentojarosite and contained 0.35 wt% Ag. Later solution precipitates were not analyzed. A chemical ferric-sulfate/forty mM Ag mixture likewise gave no centrifuge-recoverable product after fourteen days. Conversely, a separate old synthetic schwertmannite reference (100 mg, twenty mM Ag, pH 2.0 plus/minus 0.1, fourteen days; suspension volume not given) showed partial argentojarosite formation with goethite and residual material. These comparisons neither isolate cell-specific catalysis nor prove that both original culture phases are universally necessary; their solids, solution chemistry and histories differ.
Source inconsistencies are retained. Figure 6 lower traces are labeled five mM although its caption and associated prose say zero mM; the unambiguous Figure 8 fourteen-day comparison is used for the graded concentration claim. Table 9 and Figure 11 report anomalous 90.33 wt% Fe at twenty mM/eight hours and 0.37 wt% Fe for zero mM/eight hours, without a resolved analytical explanation. These values are not repaired or used for a yield. Figure 14 prints a one-hour sampling point, distinct from the main eight-hour series; only the explicitly discussed fourteen-day separated-phase outcome is adopted.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. PDF page 13, Argentojarosite row; page 1 definitions of Rd and special procedure.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15)
  2. handbook_argentojarosite: Handbook of Mineralogy. Argentojarosite, complete one-page entry. Secondary identity and substituted natural-composition context.
    https://www.handbookofmineralogy.org/pdfs/argentojarosite.pdf (accessed 2026-10-15)
  3. mukherjee2013: Mukherjee C (2013). Characterization of argentojarosite synthesized with biologically produced ferric sulfate solutions. MSc thesis, Ohio State University, Microbiology. Official OhioLink accession osu1374139251, complete 71-page deposited PDF; experimental sections 2-4, printed pages 28-53 (PDF pages 38-63), Figures 5-16 and Tables 7-10.
    https://etd.ohiolink.edu/acprod/odb_etd/ws/send_file/send?accession=osu1374139251&disposition=inline (accessed 2026-10-15)
  4. ncbi_ferrooxidans: NCBI Taxonomy species 920, Acidithiobacillus ferrooxidans. Current species name only; the thesis composite culture has no verified strain accession.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=920 (accessed 2026-10-15)
  5. mukherjee2016_context: Mukherjee C, Jones FS, Bigham JM and Tuovinen OH (2016). Synthesis of argentojarosite with simulated bioleaching solutions produced by Acidithiobacillus ferrooxidans. Materials Science and Engineering C 66:164-169. Bibliographic/abstract context for the same research lineage; the complete journal original and its graphics were not acquired, so its additional protocol details are not substituted for the inspected thesis.
    https://doi.org/10.1016/j.msec.2016.04.061 (accessed 2026-10-15)

Curation History

Timestamp Curator Action Summary
2026-10-15T11:37:59.124823Z codex (GPT-6; codex) CREATE Added argentojarosite using the complete original Mukherjee2013 thesis, separating upstream biological iron oxidation from abiotic silver-driven precipitation and retaining negative controls, source inconsistencies and absent recovery mass balance.
2026-10-15T11:44:52.009361Z codex (GPT-6; codex) EDIT Corrected the Table 9 locator to printed page 40 and PDF page 50, separately from the pages 45-51 comparison sections, following independent finding argentojarosite-round94-table9-locator; scientific quantities and limitations are unchanged.

Record source: data/records/argentojarosite.yaml