Many things are made of aluminium. Much of it is used in overhead power lines. It is also widely used in window frames and aircraft bodies. It is found at home as kitchenware, soft drink cans, and cooking foil. Aluminium is also used to coat car headlamps and compact discs. It is used in electrical transmission lines because of its light weight. It can be deposited on the surface of glass to make mirrors, where a thin layer of aluminum oxide quickly forms that acts as a protective coating. Aluminum oxide is also used to make synthetic rubies and sapphires for lasers. Aluminum can now be produced from clay, but the process is not economically feasible at today.