A magnet attracts ferrous metals and some alloys. Magnets can take three forms: natural, artificial, and electric. Natural magnets (i.e., magnetite) are very weak. Artificial magnets are made from magnetic materials (such as iron, nickel, and cobalt) and are given a strong magnetic force during construction. These are permanent magnets and have some limited use. Electromagnets can be easily turned on and off and are in common use because they are not permanent. They are called temporary magnets.