Magnesium

This alkali earth metal is the lightest of the common structural metals, and it finds its most important application in the aerospace and the automotive industries. However, low hardness and tensile strength make pure magnesium unfit for most structural applications that involve high stress. So, magnesium is mostly used in alloys that include other structural metals that enhance its mechanical properties, such as aluminium. Magnesium burns in air producing a bright light, a chemical property that is still used in pyrotechnics today.