Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite or aragonite. It often contains variable amounts of silica, clay, silt, and sand as impurities, which can give it different colors ranging from white to gray to brown.
Limestone forms through the accumulation of marine organisms such as coral, shells, algae, and microorganisms over millions of years. As these organisms die and settle on the ocean floor, their remains undergo compaction and cementation, forming limestone rock.
Limestone is commonly used in construction materials such as cement, concrete, and mortar. It's also widely used in architecture for buildings, monuments, and sculptures due to its durability and versatility. Additionally, it's utilized in industries such as agriculture, water treatment, and as a flux in steel production. Furthermore, limestone is often quarried for its use as a raw material in various industrial processes.