Alkali Feldspar Granite Composition. Less than that amount would designate the rock as a granite. The principal constituent of granite is feldspar. As shown in the qapf diagram alkali feldspar granite contains between 20 60 quartz.
Formation of alkali feldspar granite is explained below. Feldspar feldspar chemical composition.
Less quartz content would lead to quartz alkali feldspar syenite.
And t silicon si and aluminum al with a si al ratio ranging from 3 1 to 1 1. The perthitic textures in the alkali feldspars of many granites can be seen with the naked eye. Perthite is a typical texture in alkali feldspar due to exsolution of contrasting alkali feldspar compositions during cooling of an intermediate composition. As shown in the qapf diagram alkali feldspar granite contains between 20 60 quartz.
