Piece of super conducting cable made by powder in tube method, 1995-1996, by Pirelli Cables Ltd.

The superconducting material is a complex ceramic, a copper oxide containing bismuth, strontium and calcium. The wires are made by packing the powdered ceramic into tubes made of silver which are then extruded. Although it is the ceramic that carries the electrical current, you can only see the silver which surrounds it.