Cadmium

Discovered by Fredrich Stromeyer of Germany in 1817, cadmium is a blue white metal that is so soft you could cut it easily with a knife. It's name comes from Greek kadmeia, which is actually an ancient name for calamine, zinc carbonate. It makes sense, being cadmium was first discovered as an impurity in zinc carbonate.

Cadmium is a component of bearing alloys to give them resistance to fatigue, so it is often used in alloys with low melting points. However, this is not its main purpose- most cadmium is actually used in electroplating. Other than that, it is sometimes used in solder, NiCd batteries, and to control atomic fission reactions.

But even with its many uses, cadmium is in fact only found in small quantities associated with zinc. It is often obtained as a by-product during the treatment of zinc, copper, and other such metals. Cadmium and all of its components are poisonous.