What is the chemical formula for feldspar?

The chemical formula of feldspar is KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8. Feldspar is the name of a mineral group that contains silica and alumina in their composition. This group contains a wide variety of minerals, including orthoclase, microcline and plagioclase.

Feldspar is the most abundant mineral group on Earth, accounting for approximately 60 percent of all rocks, soils and unconsolidated sediments. Feldspar is mined from sand, solid granite or igneous rocks called pegmatites. Feldspar mining is a major industry for states such as North Carolina, Virginia and California. It is primarily used to lower melting temperatures during the firing process in ceramics making.