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Sabinaite mineral

Anhydrous sodium-zirconium-titanium oxycarbonate mineral with current September 2026 IMA-CNMNC approved formula Na4TiZr2O4(CO3)4, status A, and approval number IMA 1978-071. Jambor, Sturman, and Weatherly (1980) originally described the cotype specimens (NMC 61017-61024 and ROM M35902) from dawsonite-bearing silicocarbonatite sills at the Francon (St-Michel) quarry, Montreal Island, and from Mont Saint-Hilaire, Quebec, Canada. Combined electron-microprobe, atomic-absorption, and thermal-decomposition analysis on the Francon quarry type material (Table 2, p. 27) yielded Na2O 20.7, CaO 0.2, ZrO2 39.1, HfO2 0.47, TiO2 12.0, CO2 27.1 (mean of 28.1 wt% by TGA and 26.2 wt% by evolution), total 99.57 wt%, from which Jambor et al. (1980) proposed the provisional formula Na9Zr4Ti2O9(CO3)8 and a pseudo-orthorhombic/monoclinic subcell. McDonald (1996) solved the crystal structure on an untwinned crystal from Mont Saint-Hilaire in monoclinic space group C2/c (a = 10.196(1), b = 6.616(1), c = 17.958(3) A, beta = 94.14(1) degrees, V = 1208.2(3) A3, Z = 4, R = 2.1%, wR2 = 5.7% for 1564 observed reflections with F > 4sigma(F) out of 1759 unique reflections; WDS composition Na2O 19.01, ZrO2 39.20, TiO2 10.50, Nb2O5 2.02, HfO2 0.56, CO2 28.08 calc, total 99.37 wt%), proving complete ordering of 6-coordinated Ti4+ and 8-coordinated Zr4+ in polyhedral [Zr2TiO4(CO3)4]4- sheets interleaved with Na+ layers and establishing the ideal stoichiometric formula Na4Zr2TiO4(CO3)4 ( noting also that the IMA Master List misprints the 1980 Canadian Mineralogist volume as 19 instead of 18). Distinct from weloganite, dresserite, and elemental zirconium or titanium; no criticality designation, microbial mechanism, or industrial recovery yield is asserted.

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Identifiers & Classification

System Identifier Label
IMA IMA:1978-071 Sabinaite

Microbial & Biochemical Mechanisms (1)

Sabinaite other Laboratory two-stage thermal decarbona

Laboratory two-stage thermal decarbonation of sabinaite to cubic and monoclinic ZrO2

other

Heating natural Francon quarry sabinaite at 8 degrees C/min in flowing CO2 (6.8 mg sample) or N2 (7.3 mg sample) produced a two-stage decarbonation totaling 28.1 wt% mass loss (theoretical 28.0 wt% CO2 for Na4Zr2TiO4(CO3)4): a sharp first stage losing 18.8 wt% (CO2 atmosphere) or 19.3 wt% (N2 atmosphere) around the 519 degrees C endotherm to yield stabilized cubic ZrO2 (a = 5.05 A at 587 degrees C), followed by a second stage losing 9.3 wt% (CO2) or 8.8 wt% (N2) across endotherms at 660 and 780 degrees C to yield monoclinic ZrO2 (baddeleyite structure) with trace cubic ZrO2 and Na2ZrO3 at 998-1010 degrees C.

Experimental Context & Analytical Limits:
Simultaneous DTA-TGA experiments in Jambor et al. (1980), pp. 27-28, heated 6.8 mg of sabinaite in a dynamic CO2 atmosphere (to 998 degrees C) and 7.3 mg in a dynamic N2 atmosphere (to 1010 degrees C) at 8 degrees C/min, supplemented by an intermediate run quenched at 587 degrees C and room-temperature X-ray powder diffraction of the solid residues. Infrared absorption confirmed the absence of H2O or OH in unheated sabinaite.
Curated Evidence Points:
Pages 27-28 report that the 6.8 mg sample in CO2 lost 18.8 wt% in the first stage (endotherm at 519 degrees C; quenched 587 degrees C residue identified by XRD as stabilized cubic ZrO2 with a = 5.05 A) and 9.3 wt% in the second stage (endotherms at 660 and 780 degrees C), while the 7.3 mg sample in N2 lost 19.3 wt% and 8.8 wt% across the same two stages, both giving 28.1 wt% total CO2 loss and a final 998-1010 degrees C solid product of monoclinic ZrO2 plus trace cubic ZrO2 and Na2ZrO3.
Pages 812-814 show that the revised structural formula Na4Zr2TiO4(CO3)4 requires 28.08 wt% CO2 (matching the 28.1 wt% gravimetric loss measured by Jambor et al. 1980) and has two crystallographically distinct carbonate groups (C1 and C2) in equal 1:1 proportions, whereas the observed ~2:1 TGA step ratio (18.8-19.3 wt% vs 8.8-9.3 wt%) reflects kinetic intermediate phase formation rather than unequal carbonate site multiplicities.

Sources & References

  1. ima_2026_09: IMA-CNMNC, The New IMA List of Minerals, September 2026, PDF page 190, Sabinaite row: formula Na4TiZr2O4(CO3)4, status A, IMA No. 1978-071, country Canada, first reference Canadian Mineralogist 19 (1980), 25 (volume misprint for 18 (1980), 25), second reference Canadian Mineralogist 34 (1996), 811; column definitions on PDF page 1.
    https://cnmnc.units.it/files/editor/IMA_Master_List_(2026-09).pdf (accessed 2026-10-22)
  2. jambor_1980_sabinaite: Jambor JL, Sturman BD, Weatherly GC (1980), Sabinaite, a new anhydrous zirconium-bearing carbonate mineral from Montreal Island, Quebec, Canadian Mineralogist 18:25-29. Complete 5-page primary PDF visually inspected: Francon quarry and Mont Saint-Hilaire occurrences, cotypes NMC 61017-61024 and ROM M35902, optical and TEM electron-diffraction properties pp. 25-27; chemical composition Table 2, DTA-TGA thermal decomposition to cubic/monoclinic ZrO2, and powder XRD Table 3 pp. 27-29.
    https://www.rruff.net/doclib/cm/vol18/CM18_25.pdf (accessed 2026-10-22)
  3. mcdonald_1996_sabinaite: McDonald AM (1996), The crystal structure of sabinaite, Na4Zr2TiO4(CO3)4, Canadian Mineralogist 34:811-815. Complete 5-page primary PDF visually inspected: Mont Saint-Hilaire WDS composition and monoclinic C2/c single-crystal structure refinement Tables 1-4 and Figures 1-2 pp. 811-815, establishing complete Zr4+/Ti4+ ordering and revising the ideal formula to Na4Zr2TiO4(CO3)4.
    https://www.rruff.net/doclib/cm/vol34/CM34_811.pdf (accessed 2026-10-22)

Curation History

Timestamp Curator Action Summary
2026-10-22T07:20:00Z antigravity CREATE Created sabinaite mineral record with verified IMA:1978-071 identity, 1980 Francon cotype chemistry and DTA-TGA thermal decomposition mechanism, and 1996 Mont Saint-Hilaire C2/c crystal-structure refinement.

Record source: data/records/sabinaite.yaml