Mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. Minerals originate in the earth and cannot be made by living organisms. Major minerals include calcium, magnesium, phosphorus, potassium, chloride and sulfur. The body needs many minerals; these are called essential minerals. Essential minerals are sometimes divided up into major minerals (macrominerals) and trace minerals (microminerals). Minerals are used by animals and microorganisms for the process of mineralizing structures, called “biomineralization”, used to construct bones, seashells, eggshells, exoskeletons and mollusc shells.