The two components that make up the majority of Earth's crust are oxygen and silicon. Together, they form the most common mineral group, silicates, comprising about 75% of the Earth's crust. These elements combine to create various geological materials, including rocks and minerals essential for Earth's structure. The abundance of oxygen and silicon influences geological processes, including the formation of rocks, volcanism, and plate tectonics, thereby playing a crucial role in Earth's geology and the overall functioning of the planet.