AM_Hiortdahlite I_1 Formula: Na1.38 Ca4.74 Zr Y.88 Si4 O15.5 F2.5 Name: Hiortdahlite I Unit cell: 11.012 10.342 7.359 89.92 109.21 90.06 , V=791.42 Space group: P-1 (2)

Merlino S , Perchiazzi N , Mineralogy and Petrology , 37 (1987) p.25-35, The crystal structure of hiortdahlite II, Locality: Kipawa River, Canada, Note: this is a polytype of Hiortdahlite I