Metals seldom occur in their pure form in nature. They occur mostly in the form of ores, which means they are mixed with rocks. Through the process of smelting, the metal is then melted ‘out’ of the rocky mass, for instance, iron from iron ore. Even in 6000 BC there were furnaces for smelting copper ore. Metals are used mainly in the form of alloys which is a mixture of two metals. For instance, iron is often changed into steel by adding carbon. Depending upon how much carbon is mixed, the steel is either soft and can be moulded or is hard and can be used in making knife blades.
