Neptune does not have a distinct layering of its interior. However, it does have an outer-layer, a middle layer and a rocky core, probably about the mass of the Earth. The atmosphere or outermost layer is a mixture of heated gases, mainly hydrogen, helium, water and methane. The middle layer, which comprises about two-thirds of Neptune's mass is a heterogeneous combination of water, liquid ammonia, rock and methane.
Neptune's blue cloud color is the result of the absorption of red light by the methane in its atmosphere.
Composition 
