Iron

Iron is the fourth most common element in Earth's crust and makes up most of the planet's core. People have smelted it for over 3,000 years. Today it is mined as iron oxide ores such as hematite and magnetite, mostly in Australia and Brazil, and freed from oxygen in blast furnaces to make pig iron, which is then refined into steel.

Iron is one of the few elements that is naturally magnetic. In the television, it combines with oxygen as iron oxide, the raw material for steel and for magnetic ferrite, and it makes up most of the weight of the neodymium magnet in each speaker.