Diamagnetism is a form of magnetism that some materials show in the presence of a magnetic field. Diamagnetic materials are characterized by the fact that magnetization has the opposite direction with respect to the magnetic field; therefore these materials are weakly “rejected.“ This is a very weak quantum effect, which is voided if the material has other magnetic properties such as ferromagnetism or paramagnetism. In the non-scientific field, diamagnetic materials are often simply called non-magnetic.