Granite rocks contain silica, aluminum, and iron. This is because granite is an igneous rock that is primarily made up of quartz, feldspar, and mica minerals. Quartz is composed of silicon and oxygen, while feldspar contains silicon, oxygen, aluminum, and other elements such as sodium, calcium, or potassium. Mica is a group of minerals that includes silicon, oxygen, aluminum, and other elements such as iron, magnesium, or potassium. Therefore, the combination of these minerals in granite rocks results in a high content of silica, aluminum, and iron.