microcline

noun

1. (mineralogy) A common feldspar of igneous, plutonic, and metamorphic rocks, made of potassium aluminum silicate, with the chemical formula KAlSi3O8. Microcline is the main feldspar of granite. The bluish-green variety is called amazonstone, and is sometimes of gem quality. Used in ceramics, ceramic glazes, and as a scouring powder.