Citation: Piilonen, P.C.; Lalonde, A.E.; McDonald, A.M.; Gault, R.A. (2000). Niobokupletskite, a new astrophyllite-group mineral from Mont Saint-Hilaire, Quebec, Canada : description and crystal structure. Canadian Mineralogist, 38, pp. 627-639.
Formula: H4 K1.78 Mn5.98 Na1.08 Nb1.8 O31 Rb0.13 Si8 Ti0.2 Zn0.84
Chemical name: (K1.78 Rb0.13) Na0.9 (Na0.18 Mn5.98 Zn0.84) (Nb1.8 Ti0.2) (Si8 O26) (O H)4 O
List type: noninterleaving
List: 3D
Basis: (1;0;0 0;1;0 0;0;1)
Dimensionality: 3
Formula: Mn7 Na2 Nb2 O31 Si8 Ti2 Zn5 (Mn7 Na2 Nb2 O31 Si8 Ti2 Zn5)
Multiplicity: 1