Puneet Varma (Editor)

Abenakiite (Ce)

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Strunz classification
  
9.CK.10

Space group
  
R3

Crystal system
  
Trigonal

Category
  
Silicate, Cyclosilicate

Formula (repeating unit)
  
Na26Ce6(SiO3)6(PO4)6(CO3)6(SO2)O

Crystal class
  
Rhombohedral (3) H-M symbol: (3)

Abenakiite-(Ce) (IMA1991-054) is a mineral of sodium, cerium, neodymium, lanthanum, praseodymium, thorium, samarium, oxygen, sulfur, carbon, phosphorus, and silicon with a chemical formula Na26Ce6(SiO3)6(PO4)6(CO3)6(S4+O2)O. The silicate groups may be given as the cyclic Si6O18 grouping. The mineral is named after the Abenaki, an Algonquian Indian tribe of New England. Its Mohs scale rating is 4 to 5.

Contents

Occurrence and association

Abenakiite-(Ce) was discovered in a sodalite syenite xenolith at Mont Saint-Hilaire, Québec, Canada, together with aegirine, eudialyte, manganoneptunite, polylithionite, serandite, and steenstrupine-(Ce).

Crystal structure

In the crystal structure, described as a hexagonal net, of abenakiite-(Ce) there are:

  • chains of NaO7 polyhedra, connected with PO4 groups
  • columns with six-membered rings of NaO7, and NaO7-REEO6, and SiO4 polyhedra (REE - rare earth elements)
  • CO3 groups, NaO6 octahedra, and disordered SO2 ligands within the columns

    • References

    Abenakiite-(Ce) Wikipedia
    (Text) CC BY-SA