Limestone is a common type of sedimentary flagstone that is made naturally from calcium carbonate—otherwise known as the tiny calcite skeletons of microscopic organisms or the remains of fossil animal shells that lived under Earth’s water. These heavy flagstones have a natural split surface appearance and come in a range in colors including beige, black, gray, and yellow.
Limestone is available in a wide variety of specific and different stones such as chalk, which is a marine limestone; marble, which is a carbonate and typically a marine limestone; travertine, which is a sedimentary freshwater limestone; and other carbonate rocks such as dolomite. More than half of all crushed stone produced in the United States is either limestone or dolomite.
Limestone is often used for agriculture, construction, industrial applications, and more. Other end use includes carpets, glass, paint, paper, plastics, and steel. It is also used in water treatment and purification plants and for processing food, medicine, and household items.