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Switzerite mineral

Switzerite is the monoclinic manganese(II) phosphate heptahydrate mineral, ideal Mn3(PO4)2.7H2O, written Mn2+3(PO4)2(H2O)5.2H2O in the September 2026 IMA list (redefined status Rd; number 1966-042). The tetrahydrate previously called switzerite was renamed metaswitzerite; they are distinct mineral species. The microbial evidence is a qualified source assignment in streptomycete cultures, without published switzerite diffraction traces or direct hydrate determination for those products. Separate primary observations establish air dehydration of a natural Fe-bearing specimen. No criticality designation is inherited from manganese or phosphorus.

Microbial & Biochemical Mechanisms (2)

Source-assigned switzerite formation in manganese-supplemented streptomycete cultures

biomineralization Microbial

Associated Organisms: Streptomyces (NCBITaxon:1883)

Schutze2013 reports fine-grained aggregates assigned to switzerite near selected streptomycete colonies on MnCl2-supplemented actinomycete minimal medium. Strain and medium contrasts and absence of minerals on uninoculated media support a conditional culture association. Exact hydrate identity, precipitation yield and a necessary molecular mechanism remain unresolved; the assignment is not independent proof of phase-pure heptahydrate recovery.

Experimental Context & Analytical Limits:
Laboratory agar-plate assays using living spore inocula of metal-resistant isolates originally from the Ronneburg former uranium-mining area. Table 1 positive AM plus 20 mM MnCl2 rows are source-named S. acidiscabies E13, S. chromofuscus P10A-4, S. mirabilis K7A-1 and S. naganishii P9A-1. Five droplets of 3 microliters spore suspension were placed per plate; spore dose in CFU per droplet is not supplied. Plates were sealed and incubated at 28 degrees C for 56 days. Table 1 states n=3; Methods also describes duplicate plate inoculations and all treatments in triplicate without resolving their nesting. The complete AM recipe is delegated to earlier literature and phase-specific initial/final pH is not provided. Noninoculated plates and autoclaved dead biomass are stated controls, but a separate switzerite-specific dead-biomass result is not displayed. SEM uses air-dried cultures; electron-microprobe preparation uses 80 degrees C drying. XRD uses powdered samples but its hydration-preservation procedure is not specified. These treatments cannot be equated or used to establish the wet-culture hydrate.
Curated Evidence Points:
Methods 2.1 and 2.3, Results 3.1 and Table 1 (page 3608) report switzerite on AM plus 20 mM MnCl2 for exactly the four listed strain labels. Figure 1 I-J shows aggregates attributed to S. acidiscabies E13, rather than the adjacent struvite and nickel-phosphate images. Discussion page 3612 states minerals never formed on noninoculated media or at large distances from colonies. These support the source-assigned, localized culture observation; there is no measured phase-specific recovery yield.
The paper lists XRD, SEM/EDX and microprobe methods and gives the heptahydrate formula, but neither the main figures nor its one-page supplement display switzerite diffraction patterns, refined phase fractions, sample-specific water content or a switzerite composition table. Figure 3 maps manganese associated with struvite, not switzerite. The switzerite discussion cites Fanfani and Zanazzi1979, whose historical switzerite structure is the tetrahydrate renamed metaswitzerite according to White1986. The published assignment is therefore retained with an explicit hydration/identity limit rather than silently reidentified or asserted as definitive.
Table 1 reports growth without crystals in the same AM plus manganese arm for P4B-1, P10A-3, P16B-1 and P6A-1, while the sensitive TK23 strain has no growth. The TSB plus manganese arms produce struvite instead. Results 3.3/Table 4 report no switzerite on the tested soil agars despite Mn availability. These null and alternative-phase observations prevent a universal genus-wide or manganese-dose-only formation claim.
The separate nutrient-enriched soil outcome is internally inconsistent: the abstract says one strain formed switzerite on control soil, but Table 5 marks code2 (switzerite) for both S. lividans TK23 and S. mirabilis K7A-1 in column C. The conclusion says only heavy-metal-resistant strains formed switzerite despite the TK23 table entry. This record does not adopt an unambiguous soil strain count or resistance requirement. Soil incubations used 70 days and are not the 56-day supplemented-agar assay.
The sole supplement is a soil elemental-fraction table, not phase evidence or a culture recovery mass balance. Its C-soil mobile-phosphorus cell is 16 micrograms/g, whereas the main Results says phosphate was below detection in all soils/fractions. No source value is silently changed; this contradiction is not used to infer culture phosphate availability or switzerite yield.
Ammonification, urease activity and indicator-plate pH changes are separate assays, largely discussed for struvite. They do not demonstrate a required enzyme or prove their causal role in switzerite precipitation. No phase-specific metal-removal balance, purified recovered product or industrial deployment is established. The genus identifier is deliberate; source strain labels lack stock/sequence accessions in this paper.

Abiotic air dehydration of a natural Fe-bearing switzerite specimen

other

White1986 documents rapid irreversible dehydration of natural switzerite to metaswitzerite after air exposure. This is a handling-sensitive mineral transformation, not evidence that every Fe-free synthetic or cultured manganese phosphate has the same dehydration product.

Experimental Context & Analytical Limits:
Natural material from a water-filled pocket at the Foote mine, Kings Mountain, North Carolina; type specimen NMNH120871. Crystals were preserved wet. For powder diffraction, material was ground under water and sealed in a Lindemann capillary. Microprobe preparation caused dehydration; no controlled humidity/time-rate experiment or microbial culture was involved.
Curated Evidence Points:
Pages1221-1223 distinguish the wet heptahydrate from the tetrahydrate formed after minutes of air exposure, give distinct powder data in Tables1-2 and explicitly establish the IMA-accepted redefinition. The analytical fragments dehydrated during preparation, while water content for the original mineral was assigned through the accompanying crystal-structure work. These are actual qualitative transformation observations, not a fitted kinetic rate.
Page1222 compares a synthetic manganese phosphate historically labeled hexahydrate with natural switzerite: their powder patterns are nearly identical, but slight heating of the synthetic material produces a different lower hydrate, not metaswitzerite. Iron content/oxidation is proposed as an explanation and is not experimentally isolated. Thus natural Fe-bearing specimen behavior motivates, but does not prove, a particular handling alteration in the Fe-free culture material claimed by Schutze2013.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026: definitions and Switzerite row, PDF page 210; Metaswitzerite row page 142. Retained original re-inspected.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-14)
  2. handbook_switzerite: Handbook of Mineralogy, Switzerite, version 1 (2001-2005). Complete one-page identity and hydration-sensitive structure.
    https://www.handbookofmineralogy.org/pdfs/switzerite.pdf (accessed 2026-10-14)
  3. white1986: White, Leavens and Zanazzi (1986). Switzerite redefined as Mn3(PO4)2.7H2O, and metaswitzerite, Mn3(PO4)2.4H2O. American Mineralogist 71:1221-1223. Complete original, including Tables 1-2; RRUFF mirror inspected.
    https://msaweb.org/AmMin/AM71/AM71_1221.pdf (accessed 2026-10-14)
  4. schuetze2013: Schutze et al. (2013). Taking nature into lab: biomineralization by heavy metal-resistant streptomycetes in soil. Biogeosciences 10:3605-3614. Complete 10-page final original and one-page supplement; Figures 1-5 and Tables 1-5.
    https://doi.org/10.5194/bg-10-3605-2013 (accessed 2026-10-14)
  5. schuetze2013_si: Schutze et al. (2013), supplementary material: mobile and specifically adsorbed elemental concentrations in soils C, M1 and M2. Complete one-page original.
    https://bg.copernicus.org/articles/10/3605/2013/bg-10-3605-2013-supplement.pdf (accessed 2026-10-14)
  6. ncbi_streptomyces: NCBI Taxonomy 1883: Streptomyces, genus node only. Historical species/strain labels in the experiment are not equivalent to a verified current stock or sequence accession.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1883&mode=Info (accessed 2026-10-14)

Curation History

Timestamp Curator Action Summary
2026-10-14T17:19:40.181821Z codex (GPT-6; codex) CREATE Added switzerite identity, qualified strain-dependent culture assignment and independent abiotic dehydration evidence, retaining missing culture diffraction/hydration data, null arms and soil-table conflicts.

Record source: data/records/switzerite.yaml