Feldspar

Feldspars (K 8 – Na Al 8) are a group of rock-forming tectosilicate that make up about 41% of the Earth

Feldspars crystallize as both intrusive and are also present in many types of metamorphic rock Rock formed almost entirely of calcic plagioclase feldspar is known as anorthosite Feldspars are also found in many types of sedimentary rocks