gneiss punika bahan dhuwur metamorphic rock IE wis ngalami luwih Suhu lan tekanan saka Schist. iku kawangun dening metamorfosis saka wangun gneiss saka rock vulkanik, krikel utawa granitie.
biotite, chlorite, Feldspar, garnet, grafit, hornblade, micas, muscovite utawa illite, quartz, Quartzite, silika, zirkon
aluminium oxide, NaCl, cao, wesi (iii) oxide, feo, kalium oxide, Magnesium karbonat, MgO, keda, fosfor pentoxide, silikon dioksida, titanium dioxide
udan biologi, udan mechanical
erosi kimia, erosi gisik, erosi segara