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Pascoite mineral

Pascoite is a calcium decavanadate mineral with formula [Ca3(H2O)17]V5+10O28 in the September 2026 IMA list, which assigns grandfathered status G and original-description year 1914. That year is not a numbered IMA approval. Hughes and colleagues characterized a natural crystal from Harvard specimen 91449, Minasragra, Peru, and refined a disordered monoclinic C2/m structure containing [V10O28]6- units and hydrated calcium complexes. Disorder gives the Ca1 site possible local coordination by six, seven or eight oxygen atoms, averaging seven; hydrogen positions were located in difference maps but subsequently restrained, with residual disorder and partial occupancy. The 2005 paper supports this model over its tested ordered C2 alternative; it does not provide an unconstrained determination of every local hydrogen configuration. The 1966 predecessor's publisher title specifies 16H2O whereas the 2005 reference list prints 17H2O; the current identity follows the IMA formula and inspected 2005 original. The 1966 full text remains unavailable. The inspected 2005 depository files contain thermal parameters and observed/calculated diffraction intensities, but their Table 5/6 labels differ from the article's Table 4/5 deposit references; they belong to the same experiment. Pascoite is distinct from the decavanadate ion, the broader mineral group and elemental vanadium. These structural observations establish neither microbial extraction nor isolated-product recovery or industrial deployment; criticality is not inherited from vanadium.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Pascoite row, PDF page 167: [Ca3(H2O)17]V5+10O28, G, 1914; status and original-description-year definitions page 1.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-15)
  2. hughes2005: Hughes JM, Schindler M, Francis CA (2005). The C2/m disordered structure of pascoite, Ca3[V10O28]·17H2O: bonding between structural units and interstitial complexes in compounds containing the [V10O28]6- decavanadate polyanion. Canadian Mineralogist 43:1379-1386. DOI 10.2113/gscanmin.43.4.1379. Complete original inspected: specimen and methods page 1380, Tables 1-3, Figures 1-2, alternative-space-group and hydrogen-refinement limits pages 1383-1384. The article calls its deposits Tables 4-5, while the official depository labels them Tables 5-6; its printed comparative Table 5 is a different table.
    https://www.rruff.net/doclib/cm/vol43/CM43_1379.pdf (accessed 2026-10-15)
  3. swallow1966_metadata: IUCr publisher issue index for Swallow AG, Ahmed FR, Barnes WH (1966), The crystal structure of pascoite, Ca3V10O28·16H2O, Acta Crystallographica 21:397-405, DOI 10.1107/S0365110X66002974. Bibliographic title and authors verified only; full text unavailable. Used solely to retain the title's 16-water versus 2005 reference-list 17-water discrepancy, not to assert independently inspected experimental results.
    https://journals.iucr.org/q/issues/1966/09/00/index.html (accessed 2026-10-15)
  4. mac2005_deposits: Mineralogical Association of Canada, Depository of Unpublished Data. Pascoite CM43_1379, August 2005 entries: Table 5 thermal parameters (DOCX delivered through the MS_Word entry, download 1821) and Table 6 observed/calculated squared structure factors (FCF, download 1822). Both files inspected; 2844 indexed reflection rows match the total in article Table 1. These are dependent structural deposits, not independent experimental replication.
    https://www.mineralogicalassociation.ca/wordpress/depository/ (accessed 2026-10-15)

Curation History

Timestamp Curator Action Summary
2026-10-15T20:23:48.976150Z codex (GPT-6; codex) CREATE Prepared a primary-evidence mineral identity record with current IMA scope, specimen and structural interpretation limits, explicitly dependent studies and source-access boundaries.

Record source: data/records/pascoite.yaml