Ferrous metals contain iron and non-ferrous metals do not. However, it is not possible to tell which metals have iron in them and which ones do not simply by looking at them unless the person inspecting the items knows a little bit about metals and their different properties.
Ferrous metals include materials such as wrought iron, stainless steel, cast iron, carbon steel and other metals used for strength and durability. These metals are fired with a great deal of carbon, which makes them vulnerable to rust and other oxidation issues. If the piece is rusted, it is most likely ferrous. However, this is not true of wrought iron. Because it is made up of mostly pure iron, this material is rust proof. Ferrous metals are also magnetic.
Non-ferrous metals include brass, aluminum, copper, tin, nickel, lead, zinc, gold and silver among others. They differ from ferrous metals in that they are lighter and more malleable, which makes them ideal for certain industrial applications as well as for jewelry making and artistic endeavors. These metals are rust and corrosion resistant, making them ideal for outdoor use. Because they have no magnetic charge, they are also used in electrical wiring and in electronics.