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Aragonite mineral

Orthorhombic calcium carbonate mineral with ideal formula CaCO3, distinct from calcite and vaterite polymorphs, hydrated monohydrocalcite, the calcium element and carbonate-bearing resources. The September 2026 IMA list gives grandfathered status and original-description year 1791, not a new-mineral approval accession. Laboratory bacterial mineralization supports aragonite formation under specified solution conditions; it does not establish a criticality designation, a purified critical-metal product or industrial use.

Microbial & Biochemical Mechanisms (1)

Aragonite precipitation in magnesium-containing Y1 cultures

biomineralization Microbial

Associated Organisms: Bacillus licheniformis (NCBITaxon:1402)

Source-designated B. licheniformis Y1 produced aragonite-bearing precipitates in calcium- and magnesium-supplemented organic medium. At nominal Mg/Ca molar ratios 6 and 9, XRD assigned aragonite with Mg-calcite after 14 days and only aragonite among fitted crystalline phases after 25 days; at ratio 12, only aragonite was assigned at both times. At ratio 3, Mg-calcite and aragonite coexisted, while ratio 0 yielded calcite. These are phase observations in harvested solids, not mineral recovery yields or proof that every solid component is crystalline aragonite. Alkalinization and mineral association with extracellular polymeric substances are consistent with bacterial promotion of precipitation, without proving a unique molecular cause.

Experimental Context & Analytical Limits:
The study used a preserved laboratory Y1 isolate; NCBI MF808044.1 identifies a partial 16S sequence submitted as B. licheniformis Y1. The species taxon does not independently authenticate the stock. Mineralization medium contained beef extract 5 g/L, tryptone 10 g/L, NaCl 10 g/L, nominal Ca2+ 0.01 mol/L and Mg2+ 0, 0.03, 0.06, 0.09 or 0.12 mol/L supplied by CaCl2 and MgCl2·6H2O. Initial pH was adjusted to 7.0 with HCl/NaOH. A 1% v/v bacterial suspension inoculum was compared with an equal-volume sterile-water control; each Mg/Ca arm had triplicate inoculated and control groups at 37 degrees C and 130 rpm. Day-14/day-25 solids were washed three times with distilled water and anhydrous ethanol and dried before powder XRD and Rietveld fitting. The drying temperature is not specified. The reported pH rise and mineral microscopy do not replace a pH-matched cell-free phase-control series. Separate abiotic experiments added sodium carbonate to calcium/magnesium solutions with or without organic molecules and also produced aragonite; their recipe and times differ from the cultures. This is a laboratory precipitation study, not an extraction process, metal-specific recovery demonstration or deployment.
Curated Evidence Points:
Support Source: han2023
Sections 2.1-2.5 and 3.1-3.2, Figure 1 (p. 6) and Figure 2 (p. 7), support culture conditions, alkalinization and the stated time- and Mg/Ca-dependent phase assignments. Figure 3 (p. 7) associates cell/EPS-bearing aggregates with aragonite-assigned preparations; this alone does not resolve which molecular component is necessary for nucleation.
Supplementary Figure S5 panels E-H show mixed Mg-calcite/aragonite fits at day 14 and aragonite-only fits at day 25 for ratios 6 and 9; panels I-J assign aragonite at ratio 12 at both times. The 100% fit labels describe the fitted crystalline assemblage, not a mass-balance yield, exclusion of amorphous/organic material, or biological specificity. Figure S3 contrasts growth-associated pH change with the control in the biochemical growth assay.
Partial Source: han2023
Sections 2.9-2.13, 3.6-3.9 and 4.2 distinguish acid-digest Mg measurements, selected HRTEM/SAED spacings and modeled energies. Bulk Mg does not independently establish its coordination or the fraction substituting for Ca; the authors explicitly retain uncertainty about the Mg microenvironment. Section 4.3 offers alternative replacement and dissolution/reprecipitation hypotheses for selected dolomite-assigned surface domains after further incubation, without a bulk aragonite-to-dolomite conversion yield. Those inferences are not treated as demonstrated atomistic steps.
Context_only Source: han2023_si
Figure S13 includes aragonite precipitated without biomolecules in the separate sodium-carbonate experiment (main Section 2.10), preventing a claim that bacterial presence is universally necessary for aragonite formation. This abiotic experiment is not a matched substitute for the culture control.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026; definitions pp. 1-2 and Aragonite row p. 12, Ca(CO3), G, 1791.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-14)
  2. handbook_aragonite: Handbook of Mineralogy, Aragonite, CaCO3; Mineral Data Publishing, version 1, 2001-2005. Mineral identity and polymorphism.
    https://www.handbookofmineralogy.org/pdfs/aragonite.pdf (accessed 2026-10-14)
  3. han2023: Han et al. (2023). The incorporation of Mg2+ ions into aragonite during biomineralization: Implications for the dolomitization of aragonite. Frontiers in Microbiology 14:1078430. Sections 2.1-2.14 and 3-4; Figures 1-13 and Tables 1-2; complete 19-page original.
    https://doi.org/10.3389/fmicb.2023.1078430 (accessed 2026-10-14)
  4. han2023_si: Han et al. (2023), supporting information to DOI 10.3389/fmicb.2023.1078430; Supplementary Figures 1-14 and Data Sheet 1 Tables S1-S8. Phase refinement Figure S5 and separate abiotic precipitation Figure S13.
    https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1078430/full#supplementary-material (accessed 2026-10-14)
  5. ncbi_licheniformis: NCBI Taxonomy 1402, Bacillus licheniformis, species.
    https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=1402&mode=Info (accessed 2026-10-14)
  6. genbank_y1: GenBank MF808044.1, Bacillus licheniformis strain Y1 16S ribosomal RNA gene, partial sequence. Sequence-linked source designation, not a culture-collection accession or proof of the mechanism in other strains.
    https://www.ncbi.nlm.nih.gov/nuccore/MF808044.1 (accessed 2026-10-14)

Curation History

Timestamp Curator Action Summary
2026-10-14T13:15:30Z codex (GPT-6; codex) CREATE Created mineral identity and qualified Y1 aragonite precipitation mechanism from primary evidence; retained phase-fit, abiotic comparator, Mg-coordination and scale limitations.

Record source: data/records/aragonite.yaml