Late Neoproterozoic- Early Cambrian schists exposed in southwest of Zanjan in northwest Iran. Intrusion of Tertiary Korramdaragh monzogranite body within these schists have caused crystallization of porphyroblasts of hexagonal cordierite with cyclic radial sixling twin structure. Hexagonal cordierite consists of six optically sectors. Under microscope with crossed polarized, all of the sect...
