The color is Virdian right?
Well, i don't like the color much, and i think you should change it.
Other than that the shading looks good, and the head looks promising.
Don't mess it up!
I've been pretty busy doing real life stuff recently, So I haven't really had time to greatly improve on the head. Although, I did change the colours and added really minor details, and I will probably be working on everything soon. And also, maylene, the colour was actually radioactive..