The main mineral found in the Earth's crust is feldspar, which constitutes about 60% of the Earth's crust. Feldspar is a group of rock-forming silicate minerals that play a crucial role in the formation of igneous, metamorphic, and sedimentary rocks. Other significant minerals in the Earth's crust include quartz, mica, and calcite. Feldspar is vital for many geological processes and is commonly used in manufacturing glass, ceramics, and as a filler in various products. The prevalence of feldspar underlines its importance in the overall composition and functioning of the Earth's geology.