Digenite mineral
Digenite is a distinct copper sulfide mineral, listed as Cu1.8S by the September 2026 IMA list and as Cu9S5 in the Handbook of Mineralogy. IMA status is approved through 1962 special procedure, not a numbered approval accession. It is distinct from anilite, djurleite, chalcocite, covellite, copper element and mixed copper ores. The curated laboratory study uses synthesized digenite and chemical ferric sulfate; neither constituent criticality nor microbial activity is inferred.
Microbial & Biochemical Mechanisms (2)
Abiotic ferric-sulfate leaching through metastable sulfide structures
redox transformation
Ferric-sulfate concentration affected copper depletion and structural evolution of synthesized digenite grains. In-situ diffraction and separate solid microprobe analyses support chemically driven alteration through multiple metastable structures. Reported copper-leached percentages are derived from remaining-solid Cu:S ratios, not measured aqueous recovery or isolated copper yields.
Experimental Context & Analytical Limits:
Whiteside and Goble (1986) pp.248–255: research-grade copper and sulfur were sealed in evacuated silica tubes, heated and quenched using referenced synthesis methods; exact heating conditions are not restated. Sintered material was gently crushed between fingers to limit mechanical phase changes and sieved to 150–250 micrometres, with constituent crystallites generally below 50 micrometres. Several hundred grains plus quartz standard were fixed on cyanoacrylate-coated mylar for contact with freshly prepared ferric sulfate in distilled water at about 23 ±1 degrees C. The five stated concentrations were 10^-5,10^-2,10^-1,1 and2 M; solution/mineral volumes were approximately 2.25/0.001 cm3. Numerical pH and an acid-only or iron-free control are not reported. Diffraction monitored 44–50 degrees2theta with wider 35–65-degree scans after changes and Gandolfi comparisons to standards; the mylar peak prevented investigation of 25–34 degrees. Separate grains leached unmounted in sealed containers were washed, embedded, polished and analyzed by wavelength-dispersive electron microprobe at 12 kV and 1.2 nA. There was no microbial inoculum or biomass.
Whiteside and Goble (1986) pp.248–255: research-grade copper and sulfur were sealed in evacuated silica tubes, heated and quenched using referenced synthesis methods; exact heating conditions are not restated. Sintered material was gently crushed between fingers to limit mechanical phase changes and sieved to 150–250 micrometres, with constituent crystallites generally below 50 micrometres. Several hundred grains plus quartz standard were fixed on cyanoacrylate-coated mylar for contact with freshly prepared ferric sulfate in distilled water at about 23 ±1 degrees C. The five stated concentrations were 10^-5,10^-2,10^-1,1 and2 M; solution/mineral volumes were approximately 2.25/0.001 cm3. Numerical pH and an acid-only or iron-free control are not reported. Diffraction monitored 44–50 degrees2theta with wider 35–65-degree scans after changes and Gandolfi comparisons to standards; the mylar peak prevented investigation of 25–34 degrees. Separate grains leached unmounted in sealed containers were washed, embedded, polished and analyzed by wavelength-dispersive electron microprobe at 12 kV and 1.2 nA. There was no microbial inoculum or biomass.
Curated Evidence Points:
Support
Source:
whiteside1986
Figures 3–4 and Tables 1–2 show concentration-dependent copper depletion and evolving diffraction peaks, with faster change at stronger ferric-sulfate concentrations. Figure 3 explicitly uses microprobe data; Table 2 defines copper-leached values as atomic percentages inferred from changes in Cu:S. Figures 4a–b distinguish anilite and successive structural types; simultaneous structures and later changes prevent assignment of every composition to a pure natural mineral.
Partial
Source:
whiteside1986
The structural sequence compiles 13 experiments; Figure 5 separately describes 282 analyzed grains from three experiments. These are not 13 independent copper-recovery measurements. Table 2 phase proportions have approximately ±5-percentage-point precision and are based on composition/peak-intensity comparison, not a refined pure-phase mass balance. The claimed near 40% copper removal plateau in Figure 3 is a solid-composition inference, not an isolated recovery yield. Individual grains diverged, and composition samples lacked the mylar/glue mount used for in-situ diffraction, so experimental equivalence is uncertain.
Partial
Source:
whiteside1986
Pages253–258 stress that most products are metastable structural variants rather than identified natural yarrowite, spionkopite or covellite. Quenching in distilled water often failed to halt structural changes, and Gandolfi exposures integrated changing structures into broad bands. The hypothesized sulfur packing, bonding and equilibrium interpretation require further single-crystal work; no industrial performance or microbial necessity was tested. This study shares Goble authorship and explicitly builds on his 1981 natural-anilite experiment, rather than providing an independent microbial replication.
Reversible digenite–anilite structural cycling in a mounted chemical assay
other
At weak ferric-sulfate concentration, mounted synthetic digenite showed reversible diffraction changes between digenite-like and anilite-like structures. The observation is constrained to this apparatus; neither a microbial cause nor an autonomous mounting-independent mineral oscillator is established.
Experimental Context & Analytical Limits:
Same synthetic grain preparation and mylar/cyanoacrylate apparatus as the chemical leaching experiment, approximately 23 ±1 degrees C. Figure 2 follows 10^-5 M ferric sulfate. XRD peak height, base width and position were tracked, with standard comparisons. Quartz on mylar and glue was monitored as an instrumental blank; other mounting media were tried only in less controlled experiments.
Same synthetic grain preparation and mylar/cyanoacrylate apparatus as the chemical leaching experiment, approximately 23 ±1 degrees C. Figure 2 follows 10^-5 M ferric sulfate. XRD peak height, base width and position were tracked, with standard comparisons. Quartz on mylar and glue was monitored as an instrumental blank; other mounting media were tried only in less controlled experiments.
Curated Evidence Points:
Support
Source:
whiteside1986
Figure 2 and pp.250–251 show gradual growth of anilite-assigned peaks followed by rapid return of the digenite peak after about 100 minutes, with repeated cycling thereafter. The monitored quartz/mylar/glue blank did not cycle, arguing against a simple instrumental fluctuation. These observations support reversible structural behavior in the mounted digenite assay.
Partial
Source:
whiteside1986
Pages255 and 257 explicitly leave mounting dependence unresolved. The authors propose interaction through glue/mylar, including speculative electrical charging; this was not measured or established. The very dilute solutions may become ferric-ion depleted, unlike stronger arms. Similarity of unmounted composition results does not verify unmounted structural cycling. The source also reports no compositional or structural change in its separate synthetic chalcocite weak-leachate comparison for up to three years; that null belongs to chalcocite, not a digenite no-treatment control.
Sources & References
-
ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026; PDF page 57, mineral row and pages 1–2 status definitions.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-14) -
handbook: Handbook of Mineralogy. Digenite; one-page mineral description, Cu9S5 composition and temperature-dependent crystal data.
https://handbookofmineralogy.org/pdfs/digenite.pdf (accessed 2026-10-14) -
whiteside1986: Whiteside, L.S. and Goble, R.J. (1986). Structural and compositional changes in copper sulfides during leaching and dissolution. Canadian Mineralogist 24:247–258; complete twelve-page original, Figures 1–7 and Tables 1–2.
https://rruff.info/doclib/cm/vol24/CM24_247.pdf (accessed 2026-10-14)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-14T16:30:35.886892+00:00 |
codex (GPT-6; codex) | CREATE | Created distinct digenite owner with abiotic leaching and apparatus-bound reversible structural cycling; preserved mounting confounders, metastable phase uncertainty, source experiment lineage and solid-ratio recovery limits. |
Record source: data/records/digenite.yaml