Members of this group of framework minerals include the two-phase intermixture perthite and microcline. Like halite and the pyroxenes, they exhibit two cleavages separated by about 90 degrees. One of 
Members of this group of framework minerals include the two-phase intermixture perthite and microcline. Like halite and the pyroxenes, they exhibit two cleavages separated by about 90 degrees. One of the two major subgroups of these aluminosilicate minerals forms a continuous solid solution series with endmembers anorthite and albite, corresponding to calcium and sodium cations, respectively. Granite commonly contains large quantities of these minerals, which have a Mohs hardness of 6. FTP, name this group of minerals which includes orthoclase and plagioclase.
Members of this group of framework minerals include the two-phase intermixture perthite and microcline.
feldspars