The mantle is the mostly solid bulk of Earths interior, lying between the dense, super-heated core and the thin outer layer, the crust. It is composed of a variety of compounds, with the majority being silicates, which are compounds that share a silicon and oxygen structure. The main elements that make up the mantle are:

• Oxygen: 44.8%
• Silicon: 21.5%
• Magnesium: 22.8%

In addition to these three elements, the mantle also contains smaller amounts of other elements, including:

• Iron
• Aluminum
• Calcium
• Sodium
• Potassium

These elements are present in amounts greater than 1 percent in the mantle. The upper mantle, in particular, is believed to consist mainly of magnesium-iron silicates, with olivine being a significant component.