I noticed that it doesn't feel like there is metal within the plastic or rubbery wire covering.
its copper if your talking about the stuff in the wall. there are different gauges of wire(just like shotguns, smaller number=bigger wire) so if you have an older house and you are not seeing much wire its because in old work they used much less material than new work.
Its stranded copper. With a single thick conductor, it is stiff. By using many very thin wires, it is quite flexible. Look at lamps, some have clear cords, and you can see the stranded wires inside.
*Layers of copper wire or aluminium.
*A cable is one or more wires or optical fibers bound together, typically in a common protective jacket or sheath. The individual wires or fibers inside the jacket may be covered or insulated. Combination cables may contain both electrical wires and optical fibers. Electrical wire is usually copper because of its excellent conductivity, but aluminum is sometimes used because it costs less.
there must be a metal , else it won't be a wire , i mean it won't conduct elec.& 80% it's copper , unless u are talking about aspecial wire which won't be used for houses usually