What Elements Are Magnetic?
Iron, nickel, cobalt and gadolinium are naturally ferromagnetic elements. Common usage of the term "magnetic" refers to this form of magnetism. Other elements are capable of forming magnetic compounds, but are not magnetic in their pure states.
Powerful rare earth magnets are referred to by the names of their component rare earth elements, but these elements are not ferromagnetic on their own. Neodymium magnets are the best-known type of rare earth magnets and composed of an alloy of neodymium, iron and boron. Samarium magnets consist of an alloy of samarium and cobalt. These are useful at high temperatures where neodymium magnets would lose their ferromagnetism.
Other elements that are naturally nonmagnetic can undergo laboratory-induced ferromagnetism. When lithium gas is supercooled to near absolute zero, it exhibits ferromagnetism. This is the only recorded instance of a magnetic gas. While they are solids, not gases, compounds formed from actinide series elements exhibit similar magnetic properties when cooled.
The most powerful naturally occurring magnet is a compound, not a pure element: magnetite, or iron oxide. Naturally magnetized pieces of magnetite are called lodestones and have been used for their magnetic properties since ancient times. Large deposits of magnetite are magnetic enough to interfere with compasses.