What is the primary composition of Earth's crust?

The primary composition of Earth's crust is indeed oxygen, silicon, and aluminum. This is because the crust is predominantly made up of silicate minerals, which are compounds that include silica (SiO2, made of silicon and oxygen) as a major component. Additionally, aluminum is the third most abundant element in the Earth's crust, often found in minerals like feldspar and bauxite.

These elements collectively form the foundational materials that make up the various rocks and minerals found in the crust. Silicates account for about 90% of the crust's composition, which includes a wide array of minerals essential for the geology of the Earth. Understanding this composition is vital for fields such as geology, environmental science, and natural resource management, as it affects everything from soil quality to the formation of landscapes.