Depending on the sprite it is green or light blue in KQ4 (and both, but mostly blue)... Some might describe it as 'marbled'. (or if you are color blind it might appear all green)...
The sprite on the table next to the throne is 'light blue'. The small sprite as it flies through the air is 'light blue'. It's 'light blue' as it sits ont he ground from a distance.
The closeup as it spins through the air is mostly light blue, with an slight shaded edge of green. The closeup while sits on the ground is 'light blue' with slight shaded edges in green.
It was definitely light blue in the early games, KQ1, KQ2, and KQ3.
But ya, the sprites are mostly 'light blue' in KQ4, with some 'green' shading.