Plagioclase feldspar is a group of important rock-forming minerals found in many igneous, metamorphic, and sedimentary rocks. It is characterized by its two distinct cleavage planes and a range of colors, including white, gray, and sometimes even blue or green. Plagioclase is primarily composed of sodium and calcium aluminum silicate, and its composition varies between these two end members. This mineral plays a crucial role in the Earth's crust, making up a significant portion of granite and basalt. Plagioclase feldspar is also used in various industrial applications, including ceramics and glass production, due to its ability to withstand high temperatures and its chemical stability.