Steacyite

Ca_0.74Ce_0.03K_0.6Mg_0.04Mn_0.2Na_0.9O₂₀Pb_0.01Si₈Th_0.88

Prichard, P.Perrault, G.

Acta Crystallographica, Section B (1972) 28, 1994-1999

a=7.58Å   b=7.58Å   c=14.77Å

α=90°   β=90°   γ=90°