The hottest layer of the Earth is the core. The core itself contains two layers: the outer core and the inner core. Of these two, the inner core is the hottest at between 9,000 and 13,000 degrees Fahrenheit.
The Earth's core is comprised primarily of metal. The outer core contains a mixture of iron and nickel. Temperatures here reach between 7,200 and 9,000 degrees Fahrenheit. The inner cores contains iron. Shaped like a ball, it is about 750 miles thick. The outermost layer of the earth is the crust. The layer beneath the crust is the mantle, made of magma, rocks and minerals. Beneath the mantle lies the core.