They are oxygen poor. Blood turns red only when in contact with oxygen.
Somewhat blue; as, bluish veins.
It is a bluish colour
The blood in veins appears bluish because of how light interacts with the skin and the blood vessels. The oxygen-depleted blood in veins absorbs more red light and reflects more blue light, giving it a bluish hue when seen through the skin.
brownish, bluish colour
bluish grey
veins are naturally bluish, for the purple nipples.... consult a doctor!
Greenish-bluish
It is like a bluish color
brownish, bluish colour
Teal is often described as a bluish green or a greenish blue. Torquoise
Nilgai
uranus is bluish green in colour