CMMMech
CMMMech > Mineral > Senarmontite

Senarmontite mineral

Senarmontite is the cubic Sb2O3 mineral species, distinct from orthorhombic valentinite, mixed-valence antimony oxides, elemental antimony and stibnite. The September 2026 IMA list records status Rn (renamed) and year 1851. The observations below concern laboratory precipitates formed from dissolved potassium antimony(III) tartrate, not extraction of natural senarmontite ore or isolated antimony recovery. No criticality designation is inherited from the constituent element.

Microbial & Biochemical Mechanisms (2)

Senarmontite in mixed precipitates from antimonite-oxidizing enrichments

biomineralization Microbial

Live laboratory enrichment cultures derived from Channel Pond and Heap Seep sediments at the Stibnite Mine, Idaho, produced antimony-bearing precipitates during potassium antimony(III) tartrate depletion and Sb(III) oxidation. Powder XRD assigned senarmontite alongside predominantly mopungite. Senarmontite contains Sb(III), so its formation is not itself oxidation of Sb to Sb(V); it co-occurs with that transformation. These unresolved mixed communities are not assigned the taxa of subsequently isolated strains.

Experimental Context & Analytical Limits:
Sediments collected in July 2012 were stored dark at 5 degrees C for up to 11 months. Primary enrichments used 0.1 mL live sediment-microcosm inoculum in 13 mL SeFr1 medium, 0.5 g/L yeast extract and nominal 2 mM Sb(III), supplied as 1 mM C8H4K2O12Sb2.3H2O. Foam stoppers allowed air exchange; cultures were incubated statically in the dark at 27 degrees C. Secondary transfers omitted yeast extract. The paper supplies no measured culture-pH series; the field pH values are not culture setpoints. Solids were filtered and dried at 60 degrees C for 48 h before XRD, so the phase assignment applies to processed solids. Heat-sterilized and unamended enrichment controls were reported inactive, with their data not shown. Figure 2 reports means of three replicate samples and standard-deviation bars. No senarmontite-specific mass balance, separated-product purity, isolated recovery yield or industrial deployment is established.
Curated Evidence Points:
Results, Enrichment cultures and isolation, and Figure 3B show senarmontite-labelled XRD peaks in the Channel Pond precipitate alongside mopungite and medium-derived sylvite/arcanite. Yellow precipitates appeared by day 5 and darkened by day 14; Figure 3A is described as approximately day 10. The authors report mopungite as 87% and 94% of precipitated Sb species for Channel Pond and Heap Seep, respectively, with the remainder senarmontite; only Channel Pond XRD is displayed. These source-reported phase proportions are not a quantified fraction of initial feed recovered as senarmontite.
Figure 2 and the enrichment Results report less precipitation and increased dissolved Sb(V) recovery after yeast extract was omitted; the secondary Channel Pond precipitate was reported as 72% mopungite and 28% senarmontite, with XRD data not shown. Conditions therefore change the mixed product. The separate Radioisotope experiments section reports white precipitate in cell-free Sb(III)-amended tubes as well as live tubes, without assigning that precipitate's mineral identity. This prevents universal microbial-necessity claims but does not establish abiotic senarmontite. Neither observation isolates direct enzymatic crystallization from indirect changes in solution chemistry.

Reported senarmontite during growth of antimonite-oxidizing isolates

biomineralization Microbial

Associated Organisms: Hydrogenophaga sp. IDSBO-1 (NCBITaxon:1554528), Variovorax sp. IDSBO-4 (NCBITaxon:1554529)

The same Terry study reports white senarmontite precipitates during anoxic nitrate-associated growth of IDSBO-1 and aerobic growth of IDSBO-4 on antimony(III) tartrate. These are separate isolate assays, not independent replication of the study or proof that either isolate caused the enrichment-culture XRD pattern. Isolate-specific diffraction patterns are not displayed. The paper calls the isolates H. taeniospiralis and V. paradoxus from approximately 99% 16S similarity; identifiers here retain the current strain-specific NCBI entries without adopting those species assignments.

Experimental Context & Analytical Limits:
Triplicate culture tubes contained 13 mL sulfate-free SeFr2 medium without yeast extract, supplemented with vitamins and 2 mM bicarbonate. Methods specify nominal 2 mM Sb(III) as 1 mM antimony tartrate; anoxic tubes received 2 mM nitrate and were prepared using oxygen-free nitrogen. Incubation followed the 27 degrees C static culture conditions; culture pH is not reported. Antimony-free potassium sodium tartrate was tested as an alternative growth substrate, and autoclaved and unamended controls were included. Figure 7's IDSBO-4 series starts around 0.5 mM antimony tartrate, unlike the nominal 1 mM Methods formulation; no uniform dose, phase-specific yield or calculated Sb balance is imposed on those arms. HPLC monitored tartrate compounds, IC monitored Sb(V), nitrate and nitrite, and cells were counted microscopically. No biomass-specific productivity or industrial recovery process is established.
Curated Evidence Points:
Growth experiments, Figures 6A-B and 7A-B, report senarmontite in live Sb(III)-amended isolate cultures, with phase data not shown (IDSBO-4 explicitly identified by XRD). IDSBO-1 controls showed no reported senarmontite precipitation, Sb oxidation, nitrate reduction or growth without substrate. Both isolates also grew with Sb-free tartrate, so Sb(III)-based autotrophy is not demonstrated by these growth curves. The distinct radiotracer arm's inorganic-carbon uptake does not establish the cause, identity or yield of senarmontite.
IDSBO-1 did not oxidize Sb(III) aerobically, while IDSBO-4 did not oxidize it under nitrate-reducing anoxic conditions. Figures 4-5 and the Discussion provide phylogenetic and candidate-enzyme context, not a causal genetic test of senarmontite precipitation. The authors explicitly call for tartrate-free Sb(III) growth experiments and further enzyme identification. The record therefore preserves condition-specific culture association without an established molecular precipitation pathway.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. PDF page 197, Senarmontite row; page 1 definitions of Rn and year columns. Retained original rechecked.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-14)
  2. handbook_senarmontite: Handbook of Mineralogy. Sénarmontite, version 1 (2001-2005), one-page species entry. Cubic structure, formula and dimorphism with valentinite.
    https://www.handbookofmineralogy.org/pdfs/senarmontite.pdf (accessed 2026-10-14)
  3. terry2015: Terry, Kulp, Wiatrowski, Miller and Oremland (2015). Microbiological Oxidation of Antimony(III) with Oxygen or Nitrate by Bacteria Isolated from Contaminated Mine Sediments. Applied and Environmental Microbiology 81, 8478-8488. Complete PMC main text, Methods, Results, Figures 1-7, Table 1 and Discussion; no separate supplement listed in inspected main.
    https://doi.org/10.1128/AEM.01970-15 (accessed 2026-10-14)
  4. ncbi_idsbo1: NCBI Taxonomy 1554528, Hydrogenophaga sp. IDSBO-1; GenBank KM199760.1 partial 16S rRNA sequence records strain IDSBO-1. Current unresolved species assignment differs from the paper's proposed H. taeniospiralis.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1554528&mode=Info (accessed 2026-10-14)
  5. ncbi_idsbo4: NCBI Taxonomy 1554529, Variovorax sp. IDSBO-4; GenBank KM199761.1 partial 16S rRNA sequence records strain IDSBO-4. Current unresolved species assignment differs from the paper's proposed V. paradoxus.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1554529&mode=Info (accessed 2026-10-14)

Curation History

Timestamp Curator Action Summary
2026-10-14T13:57:51.245646+00:00 codex (GPT-6; codex) CREATE Created senarmontite mineral owner with qualified culture-associated precipitation, current strain identities and explicit phase, control and source-access limits.

Record source: data/records/senarmontite.yaml