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Zirconolite mineral

Zirconolite is a zirconium-bearing oxide mineral listed by IMA-CNMNC in September 2026 with formula (Ca,Y)Zr(Ti,Mg,Al)2O7 and redefined status. Its 1989 special-procedure entry is not a numbered new-mineral approval. CaZrTi2O7 is the simplified composition used in the cited nomenclature and natural-specimen study, not the measured formula of every grain. The IMA-approved nomenclature published by Bayliss et al. (1989) uses the unsuffixed name for metamict or undetermined-polytypoid material and distinguishes the 2M, 3T and 3O layered variants from cubic zirkelite. This record does not assign a particular polytypoid, space group or synthetic ceramic composition to an uncharacterized natural specimen. Bellatreccia et al. (1999) studied a natural polycrystalline aggregate collected at Jacupiranga, São Paulo, Brazil, from the locality historically associated with the name zirkelite. It was explicitly a different specimen from the historical type specimen. One hand-picked grain yielded no diffraction pattern after 48 hours in a Gandolfi camera; the authors assigned zirconolite using the metamict state and chemical composition. Three crystals examined by electron microscopy and electron microprobe showed oscillatory, sector or irregular compositional zoning. Their zirconium-bearing chemistry also included niobium, thorium, uranium, hafnium and rare-earth elements; this is specimen chemistry rather than a bulk resource grade. Table 3 separates new zirconolite analyses from the chemically distinct intergrown calzirtite. Point analyses and images support the natural occurrence, but no structure refinement of the unheated metamict specimen establishes a 2M identity. Historical heat-treated lattice parameters in Table 2 are reused from other studies, not newly measured natural-crystal structures in this investigation. The specimen's reported heavy-mineral sand provenance and carbonatitic chemical affinity do not resolve its original host rock unambiguously. Fine lamellae approach the microprobe spot size, so intermediate analyses can mix adjacent zones. The seven-oxygen cation formulae and inferred substitutions are calculations from chemistry, not direct site-occupancy or oxidation-state measurements. Figure 5 and Figure 6 captions disagree with plotted expressions or axis labels; no substitution regression is recalculated here. Tables 1-2 compile older data and do not add independent sampling. This identity and natural-specimen record makes no microbial mechanism, extraction yield, industrial deployment or inherited elemental criticality claim.

Sources & References

  1. ima_2026_09: IMA-CNMNC. The New IMA List of Minerals, September 2026. Definitions on PDF page 1 and Zirconolite row on page 242: (Ca,Y)Zr(Ti,Mg,Al)2O7, Rd, 1989 s.p. The issuing website still identifies this edition; original retained PDF re-inspected.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-12)
  2. bayliss_1989: Bayliss P, Mazzi F, Munno R and White TJ (1989). Mineral nomenclature: zirconolite. Mineralogical Magazine 53, 565-569. DOI 10.1180/minmag.1989.053.373.07. Complete five-page original and Tables 1-2 inspected; nomenclature resolutions and the 1988 IMA-CNMMN vote are on page 568. Natural and synthetic structures in Table 2 have separate provenance.
    https://doi.org/10.1180/minmag.1989.053.373.07 (accessed 2026-10-12)
  3. bellatreccia_1999: Bellatreccia F, Della Ventura G, Caprilli E, Williams CT and Parodi GC (1999). Crystal-chemistry of zirconolite and calzirtite from Jacupiranga, São Paulo (Brazil). Mineralogical Magazine 63(5), 649-660. DOI 10.1180/002646199548817. Complete twelve-page original, seven figures and three tables inspected. Specimen/methods page 650; zoning and provenance pages 651-654 and Figure 1; new analyses Table 3; derived substitutions Figures 4-6 and pages 654-658. No article-specific supplementary file was identified in the acquired original or publisher landing inventory.
    https://doi.org/10.1180/002646199548817 (accessed 2026-10-12)
  4. handbook_zirconolite: Handbook of Mineralogy. Zirconolite, version 1, copyright 2001-2005. Complete two-page original entry inspected. General identity and natural-occurrence context; its listed powder pattern is from an annealed Afrikanda specimen and is not a pattern measured from the unheated Jacupiranga specimen.
    https://handbookofmineralogy.org/pdfs/zirconolite.pdf (accessed 2026-10-12)

Curation History

Timestamp Curator Action Summary
2026-10-12T11:45:51.949257Z codex (GPT-6; codex) create Added zirconolite identity and bounded natural-specimen characterization from the complete original Bellatreccia1999 and Bayliss1989 sources, distinguishing unresolved metamict material from assigned polytypoids and historical heated or synthetic phases. Preserved analytical and source-locator limits without inventing microbial or recovery claims.

Record source: data/records/zirconolite.yaml