Limestone is a sedimentary rock consisting of more than 50% calcium carbonate (calcite – CaCO3), there are many different types of limestone formed through a variety of processes.
Limestone can be precipitated from water (non-clastic, chemical or inorganic limestone), secreted by marine organisms such as algae and coral (biochemical limestone), or can form from the shells of Dead Sea creatures (bioclastic limestone). Some limestones form from the cementation of sand and / or mud by calcite (clastic limestone), and these often have the appearance of sandstone or mudstone. As calcite is the principal mineral component of limestone, it will fizz in dilute hydrochloric acid.
The main uses of limestone and its products
Limestone (CaCO3) can be used as a building material and in the manufacturing of iron.
Glass: heated with sand and soda (sodium carbonate).
Cement: heated with clay in a kiln.
Concrete: mixed with sand, water and crushed rock
Mortar: mixed with sand and water
Slaked lime (Calcium Hydroxide Ca(OH)2): mixed with water
Lime mortar: mixed with water
Agriculture use: CaCO3(s) in limestone + acidic soil→CO2(g) + soluble calcium salts + higher soil pH