Fig. 28.-Inhomogeneous sericitization and albitization of plagioclase

A---The core part of two plagioclases (Pl1, Pl2) is sericitized, while the rim part is fresh and unaltered (An17-20). The plagioclase (Pl3) is completely sericitized. K-feldspar (K) is unsericitized; B---The rim part of plagioclase (Pl1) is sericitized, but most parts of Pl1 remain fresh and unaltered, and contain small patches of K-feldspar (antiperthite). Several crystals of surrounding plagioclase are sericitized and albitized (Ser). Cross polars. Jiling granite, Gansu Province.