The mantle is mostly made up of solid, dense and very hard rocks. It has also 44.8% oxygen, 21.5% silicon, and 22.8% magnesium, iron, aluminum, calcium, sodium, and potassium. Of course, these
elements are bound together into rocks. All of the rocks are various
oxides. The most common is SiO2 at 48%, followed by MgO – 37.8%.
