What is Earth’s crust primarily made of?

The Earth's crust is primarily composed of oxygen, silicon, and aluminum, which are fundamental building blocks of many minerals found in this outermost layer of the planet. Oxygen and silicon are the two most abundant elements in the Earth's crust, forming silicate minerals that make up a significant portion of it. Silicates, which are minerals that contain silicon and oxygen, constitute around 90% of the crust. Aluminum is also prevalent and often found in several key minerals like feldspar and bauxite.

Understanding the composition of the Earth's crust is crucial, as it influences various geological processes and helps explain the distribution of different rock types and minerals around the world. This composition is distinct from that of the Earth's core, which is made up largely of iron and nickel, or from other elements like carbon and hydrogen, which are more commonly associated with biological compounds rather than the inorganic materials that make up the crust.