Citation: Armbruster, T. (1986). Role of Na in the structure of low-cordierite: A single-crystal X-ray study Sample: from Alpe Sponda, Central Alps, Switzerland. American Mineralogist, 71, pp. 746-757.
Formula: Al3.84 Be0.16 Fe0.6 H0.6 Mg1.4 Na0.25 O18.6 Si5
List type: noninterleaving
List: 3D
Basis: (1;0;0 0;1;0 0;0;1)
Dimensionality: 3
Formula: Al16 Be8 Fe8 Mg8 O72 Si20 (Al4 Be2 Fe2 Mg2 O18 Si5)
Multiplicity: 1