Copper is a red-coloured, relatively soft, malleable metal. On contact with air, it quickly develops a thin, protective oxide layer that prevents further reactions. If copper is exposed to moist air for a long period of time, it develops a green layer of copper salts called patina, which protects the metal from corrosion. Copper is the most commonly-used non-ferrous metal in metallurgy after aluminium. It's widely used today in electric power lines because it's an excellent conductor of heat and electricity.
Copper in its pure form has properties that need to be modified to suit different uses. Pure copper isn't hard enough to withstand the stress of load-bearing, for example. It's alloyed with various other metals such as zinc, tin, nickel, aluminium, gold, silver and manganese. This enhances its properties to meet various requirements.