Calcium is a chemical element with symbol Ca and atomic number 20. Calcium is a soft gray alkaline earth metal, fifth-most-abundant element by mass in the Earth's crust. The ion Ca2+ is also the fifth-most-abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.
Three reasons Calcium stands out
- 1
Essential for bone and teeth health.
- 2
It is the most abundant mineral element in the human body by mass.
- 3
Its carbonate form makes up limestone, chalk, marble, and the shells of sea creatures.
More than bones and chalk
Calcium gives structure to shells, teeth, and skeletons, mostly through mineral compounds rather than pure metal. Cells also use tiny bursts of calcium ions as internal messages that trigger muscle contraction and many other processes. Limestone, cement, gypsum, and plaster extend calcium’s influence into cities.