My veins in some areas in my body looks blue and sort of light green. but in other areas looks purple, is this normal?

Normal.: The prominence of veins through the skin is affected by many factors including levels of hydration and dehydration, body temperature as well as outside temperature, medications and even levels of stress. Fair skinned people tend to have more easily visible veins than darker individuals and hereditary plays a strong role also. In a healthy person, visible veins are usually not of any concern.