Magnesium is an abundant metallic chemical element which has a number of industrial applications in addition to being vital for many living organisms, including humans. The atomic number of magnesium is 12, and the element is identified with the symbol Mg on the periodic table of elements. It is classified as an alkaline earth element, along with calcium and barium, among others. One of the more distinctive uses of magnesium is a source of illumination, since it burns bright white when ignited.

Sir Humphry Davy is generally credited with the discovery of magnesium, in 1808. It has been suspected that Davy actually discovered an oxide of the metal, ultimately inferring the existence of the element, but in either case magnesium was being readily extracted by the mid 1800s. One form of magnesium, epsom salts, had already been used since the 17th century, and it continues to be readily available as a bath soak. Milk of magnesia, another popular remedy, also contains magnesium.

In nature, magnesium is always found in compounds with other substances, since it is a reactive element and it will readily blend with a wide variety of things. Seawater is an excellent source of magnesium, since the element is found in high concentrations in seawater. A number of companies extract magnesium from seawater for a range of industrial uses. When isolated, magnesium is a silvery white, extremely light metal. In elemental form, magnesium is essentially nontoxic, although shavings or dust are potentially explosive. When heated, magnesium can spark toxic reactions, so facial protection should be used when working with hot magnesium.

Although magnesium is extremely light, it is also very strong. This makes it highly suitable for alloys, especially in the aerospace industry. Some high end automotives also use magnesium alloys, since the metal can lighten the overall weight of a car, making it faster and more efficient. Magnesium is also used in illumination instruments. Some chemistry teachers like to set magnesium shavings on fire to demonstrate the brilliant explosive qualities of the element for students.

In the human body, magnesium is among the top five most abundant elements. Approximately half of the body's magnesium is concentrated in the bone, and the element contributes to a number of vital biochemical reactions. Generally, a healthy diet supplies enough magnesium. An excess will lead to diarrhea, while a deficiency will cause neuromuscular problems. Leafy green vegetables happen to be a great source of magnesium, along with other vital minerals.