Here's why:
* Mantle: This layer is primarily composed of silicate minerals, which are rich in silicon and oxygen. It also contains significant amounts of iron, magnesium, calcium, and aluminum. The mantle is divided into the upper and lower mantle, with the upper mantle being more solid and the lower mantle being more fluid.
* Crust: The outermost layer of the Earth is composed of lighter rocks like granite and basalt.
* Core: The Earth's core is primarily made up of iron and nickel, with a solid inner core and a liquid outer core.
While the core is rich in iron, it's not in the form of silicate rocks. The mantle is where you'll find the iron-rich silicate rock.
