Calcium carbonate is the main component of limestone, a sedimentary rock formed primarily from marine organisms' remains, such as shells and coral. This mineral can also form through chemical precipitation in water. Limestone is commonly found in various geological formations and has significant importance in construction, agriculture, and industry. It's used for making cement, as a building material, and in road construction. Additionally, limestone plays a vital role in carbon sequestration, helping to mitigate climate change by capturing atmospheric carbon dioxide. Its versatility and abundance make it an essential resource in many sectors.