Cadmium, KAD mee uhm, is a soft, silvery-white metallic element used for plating and in alloys (mixtures of metals). Friedrich Stromeyer of Germany discovered it in 1817. For every billion atoms of Earth's crust, only about 30 are cadmium. It occurs with zinc minerals and is obtained as a by-product of zinc refining. Japan is the leading producer of cadmium.