Mimetite mineral
Mimetite is the Pb5(AsO4)3Cl mineral species, grandfathered in the September 2026 IMA list with original-description year 1832. It is distinct from elemental lead or arsenic, dissolved arsenate, the phosphate mineral pyromorphite and an unspecified lead-bearing ore. The curated experiment used a characterized but impure natural mimetite specimen. No constituent-element criticality is inherited.
Microbial & Biochemical Mechanisms (1)
Fungal transformation of natural mimetite with lead oxalate precipitation
bioleaching
Microbial
Associated Organisms:
Aspergillus niger (NCBITaxon:5061)
Laboratory cultures of Aspergillus niger ATCC 201373 grown above mimetite-containing agar produced crystals identified as lead oxalate by powder X-ray diffraction and elemental microanalysis. Mobilization followed by oxalate precipitation is the proposed interpretation of the solid-phase transformation; a dissolved-lead time course and a unique metabolic cause were not demonstrated. This observation does not establish a metal recovery yield, complete feed conversion, arsenic detoxification or industrial use.
Experimental Context & Analytical Limits:
The natural yellow specimen came from Ojuela mine, Mapimi, Durango, Mexico. Powder between 100 and 150 micrometres was oven-dried at 105 degrees C for 48 hours and added at 0.2% (w/v) to autoclaved Czapek-Dox agar at approximately 50 degrees C before pouring. Experiments used 25 mL agar in 90 mm dishes, sterile 84 mm cellophane membranes and 5 mm mycelial discs from actively growing margins of seven-day cultures. Tests were conducted at least in triplicate at 25 degrees C in the dark; the analyzed endpoint was 12 days. The membrane separated mycelium from agar while allowing nutrient and metabolite passage. The medium contained glucose, nitrate, phosphate and mineral salts, and was adjusted to pH 5.5 before autoclaving; Table 2 gives different uninoculated surface pH values after preparation. Uninoculated mineral-containing medium and mineral-free fungal growth were controls. The species identifier does not itself identify ATCC 201373 at strain level.
The natural yellow specimen came from Ojuela mine, Mapimi, Durango, Mexico. Powder between 100 and 150 micrometres was oven-dried at 105 degrees C for 48 hours and added at 0.2% (w/v) to autoclaved Czapek-Dox agar at approximately 50 degrees C before pouring. Experiments used 25 mL agar in 90 mm dishes, sterile 84 mm cellophane membranes and 5 mm mycelial discs from actively growing margins of seven-day cultures. Tests were conducted at least in triplicate at 25 degrees C in the dark; the analyzed endpoint was 12 days. The membrane separated mycelium from agar while allowing nutrient and metabolite passage. The medium contained glucose, nitrate, phosphate and mineral salts, and was adjusted to pH 5.5 before autoclaving; Table 2 gives different uninoculated surface pH values after preparation. Uninoculated mineral-containing medium and mineral-free fungal growth were controls. The species identifier does not itself identify ATCC 201373 at strain level.
Curated Evidence Points:
Support
Source:
ceci2015
Results, growth on natural mimetite, and Figure 1A-H: control crystals showed mimetite morphology and the feed diffraction matched mimetite, whereas crystals recovered below growing colonies had a diffraction pattern assigned to PbC2O4 using ICDD PDF-14-803. The product's EDXA spectrum showed Pb, C and O without the As and Cl peaks seen in feed crystals. Figure 1 presents typical observations from several determinations, reported as similar. This supports phase transformation and precipitation, not a quantified whole-feed elemental balance or proof that arsenic disappeared from the complete culture.
Partial
Source:
ceci2015
Methods call the starting specimen pure, but Table 1 reports XRF oxide-equivalent impurities including 6.40% Al2O3 by mass and a reported total of 96.07%, averaged over two determinations. Results identify mimetite as the main XRD component and qualify nondetection of other minerals by detection limits. Table 1's As2O3 reporting convention does not establish arsenic oxidation state. The Methods formula omits the arsenate subscript 3; the record identity follows IMA and the paper's complete formula elsewhere, without adopting the defective expression.
Partial
Source:
ceci2015
Crystal purification used water at 80 degrees C followed by vacuum-desiccator drying; diffraction characterizes the recovered preparation. No quantitative mineral phase fraction, isolated product yield, Pb or As mass balance, or measured arsenic fate is reported. No acid-matched, killed-biomass or cell-free-metabolite series separates the proposed causes. Table 2 supports growth-associated acidification, not an exclusive oxalate mechanism; its errors are described as relative standard deviations from more than six measurements across plates, not identified as independent biological replicates.
Partial
Source:
ceci2015
Results, growth and toxicity assessment: the reported biomass tolerance index of 97% compares treated and control mycelial dry weights and is not a mineral extraction percentage. The authors report no significant growth or dry-weight difference at this loading. Methods name one-way ANOVA on means, while Results name Kruskal-Wallis analysis on ranks and Dunn comparisons; the procedural distinction is unresolved, and extension data are not shown.
Context_only
Source:
ceci2015
Geochemical-model methods, Figure 2 and Figure 3 support an explanatory model rather than additional microbial assays. The 25 mM oxalic-acid input refers to preliminary measurements whose results are not shown. Model activities have inconsistent M versus mM reporting between the figure caption and discussion; Figure 2D depicts calcium phases although its caption names lead oxalate. No modeled fraction, stability boundary, arsenic redox pathway or transformation of another mineral is imported as a measured mimetite-culture outcome.
Sources & References
-
ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Mimetite row, PDF page 144; page 1 column definitions and page 2 distribution terms.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-11) -
mimetite_handbook: Mineralogical Society of America, Handbook of Mineralogy. Mimetite, one-page mineral description; formula and crystal data.
https://handbookofmineralogy.org/pdfs/mimetite.pdf (accessed 2026-10-11) -
ceci2015: Ceci, Kierans, Hillier, Persiani and Gadd (2015). Fungal Bioweathering of Mimetite and a General Geomycological Model for Lead Apatite Mineral Biotransformations. Applied and Environmental Microbiology 81(15):4955-4964. DOI 10.1128/AEM.00726-15; PMID 25979898; PMC4495193. Complete publisher HTML, Figures 1-3 and Tables 1-2.
https://doi.org/10.1128/AEM.00726-15 (accessed 2026-10-11) -
ncbi_niger: NCBI Taxonomy 5061. Aspergillus niger, current species node.
https://api.ncbi.nlm.nih.gov/datasets/v2/taxonomy/taxon/5061/dataset_report (accessed 2026-10-11) -
atcc201373: ATCC 201373. Aspergillus niger van Tieghem culture catalogue entry.
https://www.atcc.org/products/201373 (accessed 2026-10-11)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-11T23:32:07.515Z |
codex (GPT-6; codex) | CREATE | Curated mimetite mineral identity and qualitative fungal-associated transformation from inspected original primary evidence, retaining feed impurities, source conflicts, controls and unmeasured outcomes. |
Record source: data/records/mimetite.yaml