Magnesium

Magnesium is the lightest structural metal, about two thirds the weight of aluminum. It is one of the most common elements in Earth's crust and is also dissolved in seawater. Most is produced in China by heating dolomite rock with silicon. As a powder or thin ribbon it burns with a brilliant white flame, which is why it is used in flares and fireworks.

In the television, a small amount strengthens the aluminum alloy of the heat sink. Combined with oxygen it forms magnesium oxide, a glass ingredient. And a trace of magnesium in gallium nitride makes one side of the blue LED chip p-type, the breakthrough that made bright blue LEDs possible.