What is a common result of oxidation in rocks?

Oxidation in rocks typically involves the reaction of minerals with oxygen, leading to the alteration of those minerals. A common result of this process is the formation of iron oxide, which occurs when iron-bearing minerals undergo oxidation. This chemical reaction transforms ferrous iron (Fe²⁺) into ferric iron (Fe³⁺), resulting in various iron oxide minerals, such as hematite and goethite. These iron oxides often impart reddish or yellowish hues to the rocks, indicating that oxidation has taken place.

The other options address effects that do not directly describe oxidation processes. For instance, increased rock hardness isn't a typical result of oxidation and can vary based on numerous factors related to the specific minerals and conditions present. Similarly, while some minerals can dissolve due to chemical weathering processes, oxidation specifically refers to reactions with oxygen, not dissolution. Lastly, changes in color to white may occur through other processes, such as the formation of different minerals, rather than the direct result of oxidation where color changes generally lean towards reds, browns, or yellows due to iron oxidation.