The main mineral found in the Earth's crust is feldspar. Feldspar is actually a group of minerals that includes orthoclase, plagioclase, and microcline, and it makes up about 60% of the Earth's crust. This group of minerals is characterized by their crystalline structure and is formed from the cooling and solidification of molten rock (magma and lava). Feldspar plays a vital role in the composition of igneous, metamorphic, and sedimentary rocks. Besides, it is also essential in various industries, including ceramics, glassmaking, and as a filler in products like paint and plastics.