AM_Elpidite
Formula: Zr Si6 Na2 O18 H6
Name: Elpidite
Unit cell: 7.14 14.68 14.65 90.0 90.0 90.0 , V=1535.54
Space group: PBCM (57)

Cannillo E , Rossi G , Ungaretti L , American Mineralogist , 58 (1973) p.106-109, The crystal structure of elpidite