Bicycle Frame: anodized Aluminium? I need help with identify what materials is this frame






I need to know if this is indeed aluminium? (weight 1.2 kg for 15 inch frame hybrid, is not ferromagnetic). 
If it is, why would it have a few green/white rust, especially at the weldings/joints?

What is the material that has yellow/bronze color outside the frame? Is it a primer? Or anodized? 

I would really appreciate your help and knowledge on this matter. I would really want to paint it, but I have no idea which primer I need for this frame (aluminium or anodized...)

Disclaimer:From other question/answer (I did have a look) I guess it is aluminium, but then the rust and the color does not match Aluminium characteristics and therefore, I would like to ask.
At that weight it is 99% Aluminum. This is also backed up by the sizing of the tubes, as Aluminum has a much lower density. At the sizing and thickness of the tubing for it to be Ti/Steel it would be a considerable amount heavier.

The uniformity and consistency of the yellow/bronze would lead me to think that this is most likely anodized.