Quicklime (also known as marble), Chemical Formula：CaO , which is a common inorganic compound. It is usually made from the natural rock, which is mainly composed of calcium carbonate,is calcined at high temperature.Finally,it decompose into carbon dioxide and calcium oxide. All natural rocks,whose the main component is alcium carbonate , can be used to produce quicklime. such as limestone, chalk, dolomitic limestone, etc.