The 5-colored wires's strands looks like aluminium, but it is basically copper wire at centre, with a thin conductive coating (my teacher shown it to me) of silvery-color, so that the copper doesn't get weathered .
If the rubbery insulator removed, and the metallic strands Scrapped with a knife or a shaving-blade, the silvery-colored layer removed, and the red, copper-interior comes out.
Now, i want to know, what substance(s) used in this coating?
These wires sold as 5-color electronic wire (for low voltages). I've given a scale also. Since nothing is printed on the insulator, and i buy in retail amount (1 or 2 yard) from a large spool, i've also no clue to the datasheet right now. (however, these wires are not very costly (around Rs. 10 per yard)).