Limestone (from the Latin calx (cal. Calicis) or calcariu, “lime”) is a sedimentary rock that contains minerals with amounts above 30% of calcium carbonate (aragonite or calcite). When the predominant mineral is dolomite (CaMg (CO3) 2 or CaCO3 • MgCO3) the limestone is called dolomitic limestone.

The main impurities that limestone contains are silicas, clays, phosphates, magnesium carbonate, gypsum, glauconite, fluorite, iron and magnesium oxides, sulphides, siderite, iron dolomite sulfate and organic matter, among others.