The continental crust is the layer of granite, sedimentary and metamorphic rocks which form the continents. Geologists often refer to the rocks of the continental crust as 'Sial'. Sial stands for silicate and aluminum, the most abundant minerals in continental crust. 'Oceanic crust' is the outermost layer of Earth's lithosphere that is found under the oceans and formed at spreading centres on oceanic ridges. 'Inner core' is the inner most geologic layer of the planet Earth. It is the most remote and enigmatic part of the Earth. 'Outer core' of the Earth is solar system's largest magma chamber, consisting of mainly molten iron that consists about of Earth's mass.