A few types of materials can have permanent magnetic fields associated with them. These materials usually contain the elements iron, and/or nickel, and/or cobalt. The most common naturally occuring permanent magnet is a mineral called "magnetite" which is made up of an iron oxide ore. Cheap refrigerator magnets are made of the same stuff embedded in plastic resin. Some of the shiny metallic magnets are called "Alnico" because they are made up of an alloy containing
al
uminum,
ni
ckel, and
co
balt. "Rare earth" magnets include other elements such as samarium, and neodymium. These are very strong magnets!
