AM_Anorthoclase_1 Formula: (Al Si3) (Na.667 K.333) O8 Name: Anorthoclase Unit cell: 8.3482 12.98 7.1582 90.0 116.109 90.0 , V=696.51 Space group: C12/M1 (12)

Harlow G E , American Mineralogist , 67 (1982) p.975-996, The anorthoclase structures: The effects of temperature and composition, Grande Caldeira, Or = 32.5, T = 400 deg C, feldspar