How magnesium is obtained. It weighs only about two-thirds as much as aluminum, another widely used light metal. Magnesium was discovered in 1808 by the English chemist Sir Humphry Davy. Magnesium is a fairly abundant metallic element. But pure magnesium does not occur in nature.
Various minerals contain magnesium compounds.
A few of these compounds, primarily magnesium chloride and magnesium sulfate, occur in dissolved form in seawater and in some pools of underground water. Seawater contains 0.13 percent magnesium and provides a practically unlimited source of the metal. Magnesium plays a vital role in the life processes of plants and animals. Chlorophyll, which green plants use in photosynthesis, contains magnesium. Plants produce carbohydrates, a class of foods essential to living things, by means of photosynthesis.