Tried some material study with bronze and iron like metal.
First I roughly blocked in the highlight and shadow areas.
Then I added a light blueish tint on top for the ambient light from the sky and
a desaturated green bounce light on the bottom.
Afterwards I painted a bright blue backlight.
In the next step I focused on some details. I added scratches and wear and tear to get a more realistic rough look.
I copied the sphere and played a bit with color correction to match a iron like material as well.
I struggled with the ambient occlusion between the bottom of the sphere and the cast shadow.
I think it's quite off and the sphere is too bright on that spot maybe.