How red and yellow soils are formed? Why do they look red?

How red and yellow soils are formed? Why do they look red?

Answer:
Red soils develop on crystalline igneous rocks in areas of low rainfall in the eastern and southern parts of the Deccan Plateau.
These soils develop a reddish colour due to diffusion of iron in crystalline and metamorphic rocks. It looks yellow when it occurs in a hydrated form.

Red soil develops on crystalline igneous rocks and they looks red because of diffusion of iron and they looks yellow in hydrated forms