Rocks are composed of minerals, which are naturally occurring inorganic solids with a definite chemical composition and crystalline structure. When rocks are exposed to oxygen elements in the air, a process called oxidation takes place. Oxidation is a chemical reaction that involves the loss of electrons from an atom or molecule, resulting in an increase in its oxidation state.

In the case of rocks, the oxygen in the air reacts with certain minerals, particularly those containing iron, copper, or sulfur. These minerals undergo a series of chemical reactions that result in the formation of new compounds, such as oxides, hydroxides, and carbonates. These new compounds are typically more stable and resistant to weathering than the original minerals, which leads to the gradual alteration and breakdown of the rock.

The oxidation of rocks is an important process in the weathering and erosion of the Earth's surface. Over time, the continuous exposure to oxygen and other elements in the atmosphere can cause even solid rocks to break down and turn into soil and sediments. This process plays a crucial role in the formation of landscapes, the release of nutrients into the environment, and the shaping of the Earth's geological features.