The most abundant mineral in Earth's crust is "feldspar." This group of minerals constitutes about 60% of the Earth's crust and includes several varieties, such as orthoclase, plagioclase, and microcline. Feldspar is characterized by its aluminum silicate composition combined with other elements like potassium, sodium, and calcium. It plays a vital role in the formation of igneous, metamorphic, and sedimentary rocks. The presence of feldspar is significant in geological processes and can influence the properties and behavior of soil and bedrock.