Peridotite is a dense, dark-colored igneous rock composed primarily of olivine and pyroxene minerals. It is found in the Earth's mantle and is believed to be the main constituent of the upper mantle.

* Crust: The Earth's crust is composed of a variety of rocks, but the majority is made up of basalt and granite. These rocks are formed from the cooling and solidification of magma or lava.

* Upper Mantle: The upper mantle is composed primarily of peridotite. This rock is very dense and is subjected to intense heat and pressure.

It's important to note that the composition of the Earth's crust and mantle can vary depending on location and depth. However, peridotite is generally considered to be the dominant rock type in the upper mantle.