Powellite mineral
Powellite is the calcium molybdate mineral species Ca(MoO4), listed as grandfathered in the September 2026 IMA-CNMNC list. It is distinct from elemental molybdenum, wulfenite and an uncharacterized calcium molybdate precipitate. Sidorenko and colleagues (2008) examined black Ca-Mo-rich grains from the Bota-Burum Mo-U deposit, South Kazakhstan. Powder diffraction and infrared spectroscopy supported crystalline powellite in the uranophane-beta-associated material. Chemically similar grains from the uramarsite-associated material were optically isotropic and X-ray amorphous, with no characteristic powellite infrared bands; the authors interpreted these as metamict powellite. That interpretation is kept distinct from the directly characterized crystalline material. Radiation-induced alteration and the origin of the black colour were inferred, without a controlled irradiation test. The article's page 29 discussion is internally inconsistent about retention versus loss of anisotropy and diffraction in the silicate assemblage; the explicit characterization on pages 23-27 anchors this limited record. These observations establish neither a microbial transformation nor a mineral recovery yield. Criticality is unrecorded.
Sources & References
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ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026; PDF page 1 field definitions and page 177 Powellite row: Ca(MoO4), G, 1891. The year of first description is not a unique IMA approval accession.
https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-14) -
sidorenko2008: Sidorenko GA, Chistyakova NI, Doinikova OA, Chukanov NV, Naumova IS and Kuzmin VI (2008). Black Powellite from Molybdenum-Uranium Deposit. New Data on Minerals 43, 23-30. Complete eight-page official original inspected, including all original graphics: chemical and optical comparisons on pages 23-24; diffraction and infrared evidence on pages 25-27; missing thermal study of the amorphous arm and inconsistent phase-state discussion on page 29; proposed radiation origin on pages 29-30. Heating results on the crystalline arm are not transferred to the amorphous arm.
https://fmm.ru/images/2/23/NDM_2008_43_Sidorenko_eng.pdf (accessed 2026-10-14)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-14T21:50:00.860003+00:00 |
codex (GPT-6; codex) | CREATE | Added primary-backed powellite identity and Bota-Burum characterization, separating crystalline material from the inferred metamict arm and retaining source contradictions. |
Record source: data/records/powellite.yaml