This element is similar in its physical and chemical properties to those of its heavier peers in the alkali metal group: strontium and barium. Calcium is the fifth most abundant chemical element in the Earth’s crust, and the third metal in terms of arrangement after aluminum and iron.
It is often found there in the form of calcium carbonate compound which goes into the composition of limestone. It is also found in the form of other compounds in the gypsum, anhydrite, fluorite and apatite minerals, which are also natural raw materials for calcium.
Calcium is a chemical element with a formula Ca, and its atomic number is 20 (Note 1). It belongs to the alkaline earth metals in the second group of the periodic table of the elements. This mineral is distinguished by its chemical activity so it is not found in nature in its free form, as a layer of oxide and nitride forms on its surface when exposing to air.