Calcium is abundant within the Earth's crust. It can be mined from limestone, marble, dolomite, gypsum, anhydrite, and aragonite. Limestone sedimentary deposits can be extensive. They can be hundred of feet thick for several square miles. Thus, limestone quarries can be long-lived.
Calcium is a soft metal that makes up about 3.5 percent of the Earth's crust. It is the fifth most abundant mineral. Its name is derived from the Latin word that means lime. Lime is defined as a white, caustic alkaline substance that is made of calcium oxide and can be obtained by heating limestone.
Limestone is mined because it is used in many products. For example, limestone is used to create Portland cement and an aggregate in asphalt and concrete- all of which are important to the nation's building industry.