What is the correct definition for a Mag Wheel?  Yes, I know its a
fancy tire rim, but what exactly is it?  Someone told me that they are
made out of magnesium.  Yet, I have seen aluminum rims that people
call Mag wheels.  Of course those people could be wrong.

Do they really make wheels out of magnesium, or is it just a coating?
I know magnesium is flammable, so wouldn't it be dangerous for rims,
if for example, a brake locked and overheated.  I know all about that,
because years ago I had a disk brake lockup, and the rotor was glowing
red hot, the brake pads were burnt to a crisp, and all the grease
boiled out of my bearings and smoking like crazy.  

Anyhow, I'm getting off topic.

Thanks to all that reply

Orion