Magnets stick to materials that contain iron, nickel, and cobalt, which are known as ferromagnetic metals. These metals are naturally attracted to magnets and will firmly stick to them. Examples of ferromagnetic metals include iron, cobalt, steel, nickel, manganese, gadolinium, and lodestone. Some metals, such as rare-earth metals like samarium and neodymium, and alloys of iron, will maintain most of their magnetism even when they aren’t in a magnetic field, which is why they are known as magnetically hard and make good permanent magnets.

On the other hand, magnets wont stick to most other types of metal, including aluminum, copper, brass, lead, gold, and silver, because they are weak metals and do not contain iron, nickel, or cobalt. However, properties including iron and steel can be added to these metals to make them magnetic.

In summary, magnets stick to materials that contain iron, nickel, and cobalt, which are known as ferromagnetic metals. They wont stick to most other types of metal, including aluminum, copper, brass, lead, gold, and silver, unless these metals have been modified to contain iron or steel.