Matlockite Bannister F A, Hey M H Mineralogical Magazine 23 (1934) 587-597 The crystal-structure and optical properties of matlockite (PbFCl) Locality: Matlock, Derbyshire, England _database_code_amcsd 0014434 4.09 4.09 7.21 90 90 90 P4/nmm atom x y z Pb 0 .5 .208 F 0 0 0 Cl 0 .5 .650