Feldspar is an abundant rock-forming mineral that makes up about 60% of the Earth's crust. Feldspars are present in all types of rock formations and volcanic rocks like granite, basalt, andesite, and rhyolite. Chemically, feldspars are aluminum silicates that contain sodium, potassium, calcium or barium. Based on the predominant metal present, feldspars are classified as sodium feldspar (plagioclase), potassium feldspar (orthoclase, microcline, sanidine), and calcium feldspar (anorthite). ... Read more
