metal

Narrow by iron 20 radioactive-material 14 alloy 6 cast-iron 4 electrical-conductor 4 gold 4 lead 4 pig-iron 4 alloy-iron 2 atom 2 isotope 2 radioisotope 2 uranium 2 antimonial-lead 1 calcium 1 cesium 1 cobalt 1 copper 1 silver 1 strontium 1 thorium 1 wrought-iron 1 zinc 1