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Kësterite mineral

Kësterite is the mineral species Cu2ZnSnS4, recorded as grandfathered (G) with original-description year 1956 in the September 2026 IMA-CNMNC list. That year is not an IMA approval identifier. This natural mineral identity is distinct from elemental tin or zinc, mixed ores, synthetic CZTS photovoltaic materials, stannite and ferrokësterite. Historical papers often spell the name kesterite and describe Fe-bearing members. Černý and colleagues (2001) measured four natural Peerless pegmatite nodules, assigning two Zn-dominant specimens to ferroan kesterite from electron-microprobe composition and characterizing powder-diffraction unit cells. They explicitly named specimens by composition and did not refine cation ordering or establish each specimen's space group. Their specimens are compositionally variable natural materials, not pure endmembers. The microbial study below tested separately synthesized material identified by the historical authors as kesterite; it did not test natural kësterite, solar-cell films or industrial feed. No criticality designation is inherited from tin, zinc or copper.

Microbial & Biochemical Mechanisms (1)

Laboratory tin solubilization from synthetic kesterite in an iron-oxidizing bacterial culture

bioleaching Microbial

Associated Organisms: Acidithiobacillus ferrooxidans (NCBITaxon:920)

Teh reports tin solubilization from synthetic kesterite in an inoculated iron-oxidizing bacterial culture. Ferric-ion-mediated sulfide attack is a plausible interpretation, but the experiment does not separate direct cell action from indirect solution chemistry or establish a specific tin redox pathway. No matched sterile kesterite arm is shown, so the bacterial contribution cannot be quantified separately from acid and iron chemistry.

Experimental Context & Analytical Limits:
The historical culture was described as a pure Thiobacillus ferrooxidans strain from Kambrischer Alaunschiefer, Ranstad, Sweden, maintained in 9K medium. NCBITaxon:920 maps the species name only; no accession, molecular identification, inoculum density, assay volume, aeration, replication or uncertainty is reported. Synthetic Cu2ZnSnS4 was prepared in evacuated sealed silica tubes and reportedly verified by X-ray diffraction, without a published pattern, cation ordering refinement or quantitative phase-purity assay. No natural kësterite was tested. Figure 1 follows 35 days at 32 degrees C, particles below 0.16 mm and 0.5% pulp density. Results prose states initial pH 1.5, whereas Figures 1-2 state pH 2.5; neither value is silently preferred. A separately stated 0.1% optimum pulp density is not the Figure 1 loading. Ferrous iron was needed in nutrient medium, especially for iron-poor substrates, but its concentration is unspecified. The plotted sterile stannite comparator belongs to a different material and is not a matched kesterite control. Separate organic-acid tests used autoclaved substrates and reagents; they do not establish microbial synthesis of those leachants.
Curated Evidence Points:
Printed pages 85-87 and Figure 1 support an inoculated synthetic kesterite leaching assay with soluble tin measured by atomic absorption and confirmed colorimetrically. The reported 72.66% Sn extraction is retained as the author's percentage for this synthetic feed, not a validated natural-mineral recovery yield or isolated metal product. The plotted concentration scale labelled tin concentration (x1000 ppm) is not reconciled with feed loading, and no graph values are converted or digitized. Missing matched sterile control, replication and phase-purity data, along with the pH contradiction, limit causal and quantitative interpretation. No downstream tin isolation, product purity, solar-material recycling or industrial deployment was demonstrated.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. PDF page 112, Kësterite row (Cu2ZnSnS4, G, 1956, Russia); page 71, separate Ferrokësterite row; page 1 field definitions and page 2 distribution terms. Current diacritics and ideal formula retained.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-12)
  2. cerny_2001: Černý P, Masau M, Ercit TS, Chapman R and Chackowsky LE (2001). Stannite and kesterite from the Peerless pegmatite, Black Hills, South Dakota, USA. Journal of the Czech Geological Society 46(1-2), original printed pages 27-33; the current publisher landing page instead indexes 27-34. Complete seven-page original inspected, including Figures 1-4 and Tables 1-3; Table 1 characterizes samples PPK-2 and PPK-3, and page 29 explicitly limits naming to composition.
    https://www.jgeosci.org/content/JCGS2001_1-2__cerny2.pdf (accessed 2026-10-12)
  3. teh_1979: Teh GH (1979). Recovery of tin by geomicrobiological techniques. Warta Geologi 5(6), 85-91, November-December 1979. Official society issue PDF, article on PDF pages 3-9; complete original article and Figures 1-3 inspected. Synthetic preparation and bacterial culture on printed pages 85-86; reported extraction on page 86 and bacterial assay Figure 1 on page 89. No DOI verified.
    https://gsm.org.my/wp-content/uploads/gsm_file_2/702001-101558-PDF.pdf (accessed 2026-10-12)
  4. ncbi_ferrooxidans: NCBI Taxonomy 920, Acidithiobacillus ferrooxidans, with historical homotypic synonym Thiobacillus ferrooxidans. Species-name mapping only; it does not identify or genomically authenticate the historical Ranstad experimental strain.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=920&mode=Info (accessed 2026-10-12)

Curation History

Timestamp Curator Action Summary
2026-10-12T06:00:03Z codex (GPT-6; codex) CREATE Added current kësterite identity, qualified natural-specimen characterization and the historically assigned synthetic-feed bacterial assay. Retained missing matched controls, structural identification limits, conflicting pH and graph-scale ambiguity.

Record source: data/records/kesterite.yaml