Calcium carbonate (CaCO₃) is a very common white compound found abundantly in nature as limestone, chalk, and marble. In Pakistan, it’s crucial for the cement industry, a major contributor to the construction sector. It’s also used in agriculture to treat acidic soils, in the feed industry as a calcium supplement for livestock, and as a filler in various products like paints and plastics manufactured locally. You might also find it in some pharmaceuticals (like antacids) and even certain food products as a calcium source.