Large Round Strong Magnets Axially Magnetized NiCuNi of Zinc Coated Rare Earth Magnets A permanent magnet is that a magnet that is permanent, in contrast to an electromagnet, which only behaves like a magnet when an electric current is flowing through it. Permanent magnets are made out of substances like magnetite (Fe3O4), The most magnetic naturally occurring mineral or neodymium, Samarium cobalt, a powerfully magnetic synthetic substance.