Erythrite mineral
Erythrite is the grandfathered hydrated cobalt arsenate mineral with ideal composition Co3(AsO4)2·8H2O, a vivianite-group member. It is distinct from elemental cobalt, other end members, mixed-metal natural specimens and synthetic laboratory analogues. The experiments curated here used synthetic material; natural crystals can contain substitutions and color alone does not determine end-member identity. No criticality designation or microbial extraction claim is inferred from the constituent metal.
Microbial & Biochemical Mechanisms (2)
Laboratory precipitation and aging of a synthetic erythrite analogue
other
Majzlan et al. prepared the nominal Co100 end member by combining aqueous metal nitrate and arsenate solutions and aging the isolated solid. Powder diffraction refinements and FTIR were reported to support crystalline vivianite-type material. This supports formation of a synthetic analogue under the stated laboratory recipe, not extraction from natural ore or a recovered-metal yield.
Experimental Context & Analytical Limits:
Sections 1.2 and 2.1, printed pages 33–34 (PDF pages 3–4): the Ni–Co series used 750 mL of metal-nitrate solution with total Ni+Co 0.014 M and 250 mL of 0.02 M arsenate made from Na2HAsO4·7H2O. Both starting solutions were adjusted to pH 6 and heated to 80 °C; arsenate was added at 2 mL/min with stirring. Solids were filtered, washed, resuspended in 250 mL deionized water and aged in sealed glass bottles at 80 °C for one year before filtering, washing and room-temperature drying. Later one-month aging is a separate author-reported observation, not silently substituted for the characterized series. Ni100 and Co100 denote metal-site atomic proportions, not product mass purity or recovery percentages. No organisms, biomass or inoculated comparison were used. Synthesis replicate counts and isolated mass yields are not supplied for this claim.
Sections 1.2 and 2.1, printed pages 33–34 (PDF pages 3–4): the Ni–Co series used 750 mL of metal-nitrate solution with total Ni+Co 0.014 M and 250 mL of 0.02 M arsenate made from Na2HAsO4·7H2O. Both starting solutions were adjusted to pH 6 and heated to 80 °C; arsenate was added at 2 mL/min with stirring. Solids were filtered, washed, resuspended in 250 mL deionized water and aged in sealed glass bottles at 80 °C for one year before filtering, washing and room-temperature drying. Later one-month aging is a separate author-reported observation, not silently substituted for the characterized series. Ni100 and Co100 denote metal-site atomic proportions, not product mass purity or recovery percentages. No organisms, biomass or inoculated comparison were used. Synthesis replicate counts and isolated mass yields are not supplied for this claim.
Curated Evidence Points:
Support
Source:
majzlan_2024
Sections 2.1, 3 and 4.1; Table 2 on printed page 37 (PDF page 7), Co100 row; Figures 3–4 on printed page 36. The authors report crystalline, phase-pure members of the Ni–Co series and give fitted C2/m lattice parameters and metal proportions. The nominal end member is distinguished from the intervening solid solutions.
Support
Source:
majzlan_2024_supplement
figures-SI.pdf Figure S4, page 4, contains the Co100 end-member FTIR trace; Figure S1, page 1, gives Ni–Co lattice trends. These are supporting characterization from the same study, not independent replication or an elemental mass balance.
Partial
Source:
majzlan_2024
Sections 2.1 and 4.1 distinguish input metal ratios from product composition and report failed Ni–Cu and Ni–Zn syntheses containing olivenite or adamite. The available powder data did not support refinement of complete atomic positions/site occupancies. Those failures and characterization limits prevent extrapolating this recipe to arbitrary metal mixtures or universal phase-pure recovery.
Acid dissolution of the synthetic analogue during calorimetry
other
The synthetic erythrite end member dissolved in hydrochloric acid during a heat-flow measurement. The reported dissolution observation is laboratory acid chemistry; its enthalpy is not a microbial effect, environmental dissolution rate, equilibrium concentration or isolated cobalt product yield.
Experimental Context & Analytical Limits:
Section 3, printed page 35 (PDF page 5), and Section 4.2, printed page 37 (PDF page 7): approximately 10 mg sample pellets were dropped into 25 g of 5 N HCl in an isothermal calorimeter at 298.15 K after overnight stabilization. Table 3 identifies the solvent as 5 N HCl at 25 °C and gives two calorimetric measurements for each end member. This assay is separate from the ICP-OES digestion with 15 mL of 0.5 M HCl, where some Ni-rich specimens were heated to 70 °C for 10 minutes. Neither protocol is a natural-ore bioleaching experiment.
Section 3, printed page 35 (PDF page 5), and Section 4.2, printed page 37 (PDF page 7): approximately 10 mg sample pellets were dropped into 25 g of 5 N HCl in an isothermal calorimeter at 298.15 K after overnight stabilization. Table 3 identifies the solvent as 5 N HCl at 25 °C and gives two calorimetric measurements for each end member. This assay is separate from the ICP-OES digestion with 15 mL of 0.5 M HCl, where some Ni-rich specimens were heated to 70 °C for 10 minutes. Neither protocol is a natural-ore bioleaching experiment.
Curated Evidence Points:
Support
Source:
majzlan_2024
Section 3 and Section 4.2 report rapid, reproducible dissolution in the calorimetric solvent; Table 3 on printed page 38 (PDF page 8) contains the Co100 dissolution-enthalpy row with its number of measurements. This supports the bounded dissolution observation, without assigning a timed rate or metal-recovery fraction.
Partial
Source:
majzlan_2024
The paper derives thermodynamic solubility products from calorimetry and discusses differing results and incongruent dissolution in earlier literature. Those derived constants are not direct measurements of a recovered product or proof of equilibration in a microbial system; the older experiments have not been independently adopted here.
Sources & References
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ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Erythrite row, PDF page 65; page 1 defines G as grandfathered and 1832 is an original-description year, not a modern approval identifier.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15) -
majzlan_2024: Majzlan, Reichstein, Haase, Stevko, Sejkora and Dachs (2024). Thermodynamics of vivianite-group arsenates M3(AsO4)2·8H2O (M is Ni, Co, Mg, Zn, Cu) and chemical variability in the natural arsenates of this group. European Journal of Mineralogy 36, 31–54. DOI:10.5194/ejm-36-31-2024. Sections 1.2, 2.1, 3, 4.1 and 4.2; Tables 2–3 and Figures 3–4.
https://ejm.copernicus.org/articles/36/31/2024/ (accessed 2026-10-15) -
majzlan_2024_supplement: Majzlan et al. (2024), official supplement to DOI:10.5194/ejm-36-31-2024. figures-SI.pdf, Figure S1 (page 1) and Figure S4 (page 4), with composition-labeled lattice trends and FTIR spectra; companion files belong to the same experiment.
https://ejm.copernicus.org/articles/36/31/2024/ejm-36-31-2024-supplement.zip (accessed 2026-10-15)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-15T12:42:47Z |
codex (GPT-6) | create | Created erythrite mineral owner with separately scoped synthetic precipitation and calorimetric acid dissolution from complete Majzlan2024 primary and supplement; verified dated IMA identity and retained natural/synthetic, control, yield and access limits. |
Record source: data/records/erythrite.yaml