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Wollastonite mineral

Wollastonite is the calcium silicate mineral species CaSiO3, listed as approved with the literal 1962 s.p. entry in the September 2026 IMA list. It is distinct from elemental silicon or calcium, a calcium-silicate commodity, and mixed rock or waste feed. The experimental natural crystals are source-assigned wollastonite; the study does not establish an exact polytype or complete phase purity for the bacterial-assay batch. No constituent criticality is inherited.

Microbial & Biochemical Mechanisms (1)

Live versus heat-killed Pseudomonas dissolution assay with limited enhancement evidence

bioleaching Microbial

Associated Organisms: Pseudomonas chlororaphis subsp. aureofaciens (NCBITaxon:587851)

Natural wollastonite released calcium and silica in both live and heat-killed bacterial suspensions. The authors interpreted the overall live-cell advantage as small relative to experimental uncertainty. This records a tested microbial interaction and its limited outcome, not proof that microbial weathering is generally ineffective or that calcium or silicon was recovered as a product.

Experimental Context & Analytical Limits:
Pokrovsky et al. used source-named Pseudomonas aureofaciens CNMN PsB-03, a soybean-rhizosphere isolate supplied by the Moldovan institute, grown for 48 h at 28 degrees C on sucrose-peptone (SP, EPS-rich) or succinate (SA, EPS-poor) medium. Washed live cells were compared with biomass autoclaved at 130 degrees C for 30 min in each nutrient medium and in 0.01 M NaCl. Batch assays ran at 25 +/- 1 degrees C and 120 rpm for up to seven days using sterile 50-100 micrometre mineral powder; eight live/dead condition combinations are described, without a clear independent reactor-replicate count. Methods give 0.5 g mineral in 250 mL but call this 2.5 g/L, an unresolved arithmetic discrepancy also carried into Table 3. Live biomass varied approximately 0.5-4 g wet/L; dead biomass was 1.5 g wet/L. Figure 5 pH labels span 7.2-8.2, whereas nutrient SP Figure 6 spans 7.3-6.5 despite Table 3 giving 7.2-8.2 generally. Calcium and silica were measured in 0.22-micrometre filtrates by atomic absorption and molybdate-blue colorimetry. Sterile contamination controls and separate abiotic mixed-flow comparisons are described; the plotted matched batch contrasts are live versus dead biomass, not a complete biomass-free kinetic series.
Curated Evidence Points:
Figures 5-6 and Table 3 show dissolution in live and dead suspensions, with some larger live-culture silica slopes. The authors conclude that their pooled enhancement is within experimental uncertainty. That conclusion is retained as their interpretation, not a uniformly null result: Table 3 SA-medium log silica rates (-12.08 live versus -12.43 dead) imply a larger ratio than the stated 55 percent, while the stated 37 percent SP exception also does not match its listed rates. Figure 6 labels SP silica as ppm and SA silica as mM; no silent unit correction, pooled enhancement estimate, exact rate or yield is adopted. Source batch loading, pH and replication limits prevent precise cross-arm effect claims.
Context_only Source: berner2010
The published comment challenges extending the wollastonite result to basalt weathering and general biological control, noting aluminium- and iron-bearing mineral differences and field evidence. It does not repeat or invalidate this particular live/dead assay.
Context_only Source: reply2010
The authors agree that wollastonite is a misleading general proxy for most basic igneous rocks and narrow the extrapolation. This record therefore makes no claim that all soil biota, silicates or field systems lack enhanced dissolution, and no carbon-sequestration or industrial-recovery claim.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026; definitions PDF pages 1-2, Diopside row page 57 and Wollastonite row page 235.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-14)
  2. handbook: Handbook of Mineralogy. Wollastonite, version 1.2 (2001), two-page entry; identity and polytypes.
    https://www.handbookofmineralogy.org/pdfs/wollastonite.pdf (accessed 2026-10-14)
  3. pokrovsky2009: Pokrovsky et al. (2009). Effect of Organic Ligands and Heterotrophic Bacteria on Wollastonite Dissolution Kinetics. American Journal of Science 309:731-772. DOI 10.2475/08.2009.05; bacterial methods pp734-735,739, results pp754-756, Figures 5-6, Table 3 and Appendix 2.
    https://doi.org/10.2475/08.2009.05 (accessed 2026-10-14)
  4. berner2010: Berner (2010). Comment: Effect of Organic Ligands and Heterotrophic Bacteria on Wollastonite Dissolution Kinetics. American Journal of Science 310:424. DOI 10.2475/05.2010.04; criticism of generalization to basalt and soil biota.
    https://doi.org/10.2475/05.2010.04 (accessed 2026-10-14)
  5. reply2010: Pokrovsky et al. (2010). Reply to Comment by Robert A. Berner. American Journal of Science 310:425-426. DOI 10.2475/05.2010.05; acknowledged limits on extrapolation.
    https://doi.org/10.2475/05.2010.05 (accessed 2026-10-14)
  6. ncbi_aureofaciens: NCBI Taxonomy 587851, Pseudomonas chlororaphis subsp. aureofaciens; official XML lists Pseudomonas aureofaciens as synonym. Checked 14 October 2026; name mapping does not authenticate CNMN PsB-03.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=587851&mode=Info (accessed 2026-10-14)

Curation History

Timestamp Curator Action Summary
2026-10-14T10:05:32.169604+00:00 codex (GPT-6; codex) CREATE Created mineral record from controlled primary microbial dissolution studies, retaining null/limited outcomes, source inconsistencies and limits on causal and field extrapolation.

Record source: data/records/wollastonite.yaml