Eudialyte group

Eudialyte group is a group of complex trigonal zircono- and, more rarely, titanosilicate minerals with general formula [N(1)N(2)N(3)N(4)N(5)]3[M(1a)M(1b)]3M(2)3M(4)Z3[Si24O72]O'4X2, where N(1) and N(2) and N(3) and N(5) = Na+ and more rarely H3O+ or H2O, N(4) = Na+, Sr2+, Mn2+ and more rarely H3O+ or H2O or K+ or Ca2+ or REE3+ (rare earth elements), M(1) and M(1b) = Ca2+, M(1a) = Ca2+ or Mn2+ or Fe2+, M(2) = Fe (both II and III), Mn and rarely Na+, K+ or Zr4+, M(3) = Si, Nb and rarely W, Ti and [] (vacancy), M(4) = Si and or rarely [], Z Zr4+ and or rarely Ti4+, and X = OH−, Cl− and more rarely CO32− or F−. Some of the eudialyte-like structures can even be more complex, however, in general, its typical feature is the presence of [Si3O9]6− and [Si9O27]18− ring silicate groups. Space group is usually R3m or R-3m but may be reduced to R3 due to cation ordering.[1] Like other zirconosilicates, the eudialyte group minerals possess alkaline ion-exchange properties, as microporous materials.[2]

List of the eudialyte-group minerals

Approved species
  • Alluaivite - Na
    19    (Ca,Mn)
    6    (Ti,Nb)
    3    Si
    26    O
    74    Cl·2H2O     (space group R-3m)
  • Andrianovite - Na
    12    (K,Sr,Ce)
    3    Ca
    6    Mn
    3    Zr
    3    NbSi(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    O(O,H
    2    O,OH)
    5     (space group R3m)
  • Aqualite - (H
    3    O)
    8    (Na,K,Sr)
    5    Ca
    6    Zr
    3    Si
    26    O
    66    (OH)
    9    Cl     (space group R3)
  • Carbokentbrooksite - (Na,[ ])
    12    (Na,Ce)
    3    Ca
    6    Mn
    3    Zr
    3    Nb(Si
    25    O
    73    )(OH)
    3    (CO
    3    )·H2O     (space group R3m)
  • Davinciite - Na
    12    K
    3    Ca
    6    Fe2+
    3    Zr
    3    (Si
    26    O
    73    OH)Cl
    2     (space group R3m)
  • Dualite - Na
    30    (Ca,Na,Ce,Sr)
    12    (Na,Mn,Fe,Ti)
    6    Zr
    3    Ti
    3    Mn(Si
    51    O
    144    )(OH,H
    2    O,Cl)
    9     (space group R3m)
  • Eudialyte - Na
    15    Ca
    6    (Fe,Mn)
    3    Zr
    3    (Si
    3    O
    9    )
    2    SiO(Si
    9    O
    27    )
    2    (O,OH,H
    2    O)
    3    (OH,Cl)
    2     (space group R-3m)
  • Feklichevite - Na
    11    Ca
    9    (Fe3+,Fe2+)
    2    Zr
    3    Nb[Si
    25    O
    73    ](OH,H
    2    O,Cl,O)
    5     (space group R3m)
  • Fengchengite - Na
    12    [ ]
    3    (Ca,Sr)
    6    Fe3+
    3    Zr
    3    Si(Si
    25    O
    73    )(H
    2    O,OH)
    3    (OH,Cl)
    2     (space group R-3m)
  • Ferrokentbrooksite - Na
    15    Ca
    6    (Fe,Mn)
    3    Zr
    3    NbSi
    25    O
    73    (O,OH,H
    2    O)
    3    (Cl,F,OH)
    2     (space group R3m)
  • Georgbarsanovite - Na
    12    (Mn,Sr,REE)
    3    Ca
    6    Fe
    3    Zr
    3    NbSi
    25    O
    76    Cl
    2    ·H2O     (space group R3m)
  • Golyshevite - (Na
    10    Ca
    3    )Ca
    6    Zr
    3    Fe
    2    SiNb(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (OH)
    3    (CO
    3    )·H2O     (space group R3m)
  • Ikranite - (Na,H
    3    O)
    15    (Ca,Mn)
    6    Fe3+
    2    Zr
    3-4    SiO(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    ·2− 3H
    2    O     (space group R3m)
  • Ilyukhinite - (H
    3    O,Na)
    14    Ca
    6    Mn
    2    Zr
    3    Si
    26    O
    72    (OH)
    2    ·3H2O     - the most recent add (space group R3m)[3]
  • Johnsenite-(Ce) - Na
    12    (Ce,La,Sr,Ca)
    3    Ca
    6    Mn
    3    Zr
    3    WSiO(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (CO
    3    )(OH,Cl)
    2    ·H2O     (space group R3m)
  • Kentbrooksite - (Na,REE)
    15    (Ca,REE)
    6    (Mn,Fe)
    3    Zr
    3    (Si
    3    O
    9    )
    2    SiO(Si
    9    O
    27    )
    2    (O,OH,H
    2    O)
    3    F
    2    ·2H2O)     (space group R3m)
  • Khomyakovite - Na
    12    Sr
    3    Ca
    6    Fe
    3    Zr
    3    (W,Nb)SiO(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (O,OH,H
    2    O)
    3    (OH,Cl)
    2     (space group R3m)
  • Labyrinthite - (Na,K,Sr)
    35    Ca
    12    Fe
    3    Zr
    6    TiSi
    51    O
    144    (O,OH,H
    2    O)
    9    Cl
    3     (space group R3)
  • Manganokhomyakovite - Na
    12    Sr
    3    Ca
    6    Mn
    3    Zr
    3    (W,Nb)SiO(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (O,OH,H
    2    O)
    3    (OH,Cl)
    2     (space group R3m)
  • Manganoeudialyte - Na
    14    Ca
    6    Mn
    3    Zr
    3    [Si
    26    O
    72    (OH)
    2    ]Cl
    2    ·4H2O     (space group R3m)
  • Mogovidite - Na
    9    (Ca,Na)
    5    Ca
    6    Zr
    3    Fe
    2    (SiNb)(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (CO
    3    )(OH,H
    2    O)
    3    Cl
    0.3     (space group R3m)
  • Oneillite - Na
    15    Ca
    3    Mn
    3    Fe2+
    3    Zr
    3    Nb(Si
    25    O
    73    )(O,OH,H
    2    O)
    3    (OH,Cl)
    2     (space group R3)
  • Raslakite - Na
    15    Ca
    3    Fe2+
    3    (Na,Zr)
    3    Zr
    3    (Si,Nb)SiO(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (OH,H
    2    O)
    3    (Cl,OH)     (space group R3)
  • Rastsvetaevite - Na
    27    K
    8    Ca
    12    Fe
    3    Zr
    6    Si
    52    O
    144    (O,OH,H
    2    O)
    6    Cl
    2     (space group R3m)
  • Taseqite - Na
    12    Sr
    3    Ca
    6    Fe
    3    Zr
    3    NbSiO(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (O,OH,H
    2    O)
    3    Cl
    2     (space group R3m)
  • Voronkovite - Na
    15    (Na,Ca,Ce)
    3    (Mn,Ca)
    3    Fe
    3    Zr
    3    Si
    26    O
    72    (OH,O)
    4    Cl·H2O     (space group R3)
  • Zirsilite-(Ce) - (Na, [ ])
    12    (Ce,Na)
    3    Ca
    6    Mn
    3    Zr
    3    Nb(Si
    25    O
    73    )(OH)
    3    (CO
    3    )·H2O     (space group R3m)

Unnamed species

The list of eudialyte-related natural phases is growing. There are many such phases, some of them very complex, coded "UM" by the International Mineralogical Association, and include:[4][5]

  • UM-1971-22-SiO:CaClFeHMgMnNaNbZr - Na
    12    Ca
    5    (Ce,La,Y,Ca)Zr
    3    (Zr,Nb)(Fe,Mn)
    3    [Si
    9    O
    24-26    (OH)
    1-3    ]·2(Si
    3    O
    9    )
    2    Cl     - with variable substitution of OH for oxygen
  • UM1990-79-SiO:CaClFeHMnNaNbREEZr - Na
    14    Ca
    5    (Mg,Ca,Mn)Zr
    3    (Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (Si,Nb,Al,Zr)
    2    (Fe,Zr)
    3    (Mn,Na,Ce,La,Y)(Na,H
    2    O,K,Sr)(OH)
    4-5    (OH,Cl)     - first representative with magnesium-dominant site
  • UM1990-80- SiO:CaFeHMnNaNbREEZr - Na
    14    Ca
    4    (Mn,Ca)
    2    Zr
    3    (Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (Si,Nb,Al,Zr)
    2    (Fe,Mn,Al,Ti)
    3    (Na,Ce,La,Y,Mn)(Na,H
    2    O,K,Sr)(OH)
    7-8
  • UM1998-21-SiO:CaCeClHMnNaZr - Na
    16    Ca
    6    (Mn,Ce)
    3    Zr
    3    (Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (OH,Cl)
    4
  • UM1999-36-SiO:CaCeHMnNaNbSrZr - Na
    17    Mn
    3    Ca
    2    Zr
    3    Si
    26    O
    72    (OH,F,Cl)
    4
  • UM2000-66-SiO:CaClFeHMnNaNbSrZr - Na
    12    (Ca,Mn)
    6    (Sr,Na,K)
    3    (Fe,Mn)
    3    (Zr,Nb)
    4    Si
    25    O
    66    (OH,Cl)
    11
  • UM2003-39- SiO:CaClFeHHfNaNbSrTaTiZr - Na
    12    (Na,K,Mn,Sr)
    2    Ca
    5    (Ca,Mn)(Zr,Hf)
    3    (Fe,[ ],Ta)
    3    (Si,Nb,W)(Si,Al,Ti)Si
    24    O
    72    (OH,O)
    33.5    Cl·1.2H2O
  • UM2004-51-SiO:CaClFFeHNaNbTi' - Na
    16    Ca
    6    (Fe,Mn)
    3    Zr
    3    (Ti,Nb)Si
    26    O
    72    FCl
    0.5    ·nH
    2    O
  • UM2006-17-SiO:CaClFFeHMnNaZr - Na
    15    (Ca
    3    Mn
    3    )Zr
    3    (Fe,Zr)
    3    SiSi(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    O
    2    (OH,F,Cl)
    3    ·2H2O
  • UM2006-18-SiO:CaClFFeHMnNaZr - Na
    15    Ca
    3    (Mn,Fe)
    3    Zr
    3    (Zr,Na)
    3    (Si,Nb)(S,Ti,Si)(Si
    3    O
    9    )
    2    (Si
    9    O
    27    )
    2    (O,OH)
    5    (Cl,F,H
    2    O)     - with essential sulfur and with Zr dominant in two sites
  • UM2006-28-SiO:CaHMnNaZr - Na
    33    Ca
    12    Zr
    6    Mn
    3    (Mn,Nb,Ti)
    2    Si
    50    O
    132    (O,OH)
    12    (OH,H
    2    O,Cl)
    10     - with double c unit cell dimension

In addition, there is "eudialyte 3248": Na
29Ca
12Zr
6[Si
48O
132(O,OH)
12]{[Na]
4[Si]
2{[Mn]
3[Mn,Nb,Ti]
2}(OH,H
2O,Cl)
10, plus admixtures of Ce, Sr, Ba and Y, characterized by one S-dominant site (not shown in the simplified formula)[6]

Other species

Rastsvetaeva et al. (2015) describe a species tentatively called "hydrorastsvetaevite", with a formula (Na
11(H
3O)
11K
6(H
2O)
1.5Sr)Ca
12Fe
3Na
2MnZr
6Si
52O
144(OH)
4.5Cl
3.5.[7]

Further reading

References
  1. Johnsen, O.; Ferraris, G.; Gault, R. A.; Grice, J. D.; Kampf, A. R.; Pekov, I. V. (2003). "The Nomenclature of Eudialyte-Group Minerals". The Canadian Mineralogist. 41 (3): 785–794. doi:10.2113/gscanmin.41.3.785.
  2. Zubkova, Natalia V.; Pushcharovsky, Dmitrii Yu. (2008). Mixed-Framework Microporous Natural Zirconosilicates : Minerals as Advanced Materials I. pp. 45–56. doi:10.1007/978-3-540-77123-4_6. ISBN 978-3-540-77122-7.
  3. Hålenius, U.; Hatert, F.; Pasero, M.; Mills, S. J. (2015). "New minerals and nomenclature modifications approved in 2015". Mineralogical Magazine. 79 (7): 1859–1864. doi:10.1180/minmag.2015.079.7.18.
  4. Mindat, http://www.mindat.org
  5. Smith, D.G.W., and Nickel, E.H.N., 2007. A System of Codification for Unnamed Minerals: Report of the SubCommittee for Unnamed Minerals of the IMA Commission on New Minerals, Nomenclature and Classification. Canadian Mineralogist v. 45, p.983-1055; http://nrmima.nrm.se/Valid2012.pdf
  6. Rastsvetaeva et al. 2006, in: Ercit et al. 2007, https://link.springer.com/article/10.1134/S1028334X06070166
  7. Rastsvetaeva, R. K.; Aksenov, S. M.; Rozenberg, K. A. (2015). "Crystal structure and genesis of the hydrated analog of rastsvetaevite". Crystallography Reports. 60 (6): 831–840. Bibcode:2015CryRp..60..831R. doi:10.1134/S1063774515060279.
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