Magnesium was first discovered by an English chemist named Sir Humphry Davy. In 1808, he successfully isolated magnesium through the electrolysis of a combination of mercuric oxide and magnesium oxide. In modern times, magnesium can be obtained from the minerals carnallite and dolomite, but it is primarily extracted from salt water found in oceans.
The element magnesium is the seventh most plentiful element found in the Earth's crust, but it does not exist freely in nature. Magnesium is used in the construction of flares, photographic flashbulbs and pyrotechnics because of the extremely bright white light that it emits when burned. It is also used to make inks, paints, antacids and laxatives, and it is alloyed with metals that are used for manufacturing rockets, missiles and airplanes.