Cu & TiNb
Superconductor is composed of copper metal surrounding rods of titanium-niobium alloy. The alloyed rods go throughout the material, making a dotted or other pattern when cut in a cross section. It is primarily used for having zero electrical resistance when cooled to low temperatures. Superconductor pieces can be etched in strong acids such as ferric chloride. This process eats away at the copper but not at the titanium-niobium metal, creating interesting forms and shapes in jewelry made with it.
This is a slightly etched super conductor pendant. The outside copper has been dissolved away, making the titanium-niobium alloy slightly raised.