Limestone is a sedimentary rock formed primarily from calcium carbonate. These are generally light colored due to the presence of calcium and can also contain fossil fuels like corals, shells etc as these also comprise of calcium carbonate. Limestone can be easily be found all over the world in the bedrock. Because of its easy availability, limestone is a popular stone for building construction. Depending on the forming conditions, limestone can be granular, massive, crystalline or clastic in appearance. It is easy to identify limestone fields through acid testing since calcium carbonate reacts with hydrochloric acid.
Most limestones have granular structure as these are basically skeletal animals that accumulate after death and through lithification turn into limestone. These are called biological sedimentary rocks. Other way of limestone formation is the direct deposition of calcium carbonate from marine or fresh water that is chemical sedimentary rock. Although these are available in less amount these are still used as any other limestone stock. Travertine, chalk, tufa, caliche, sparite and micrite are all different varieties of limestone.
- Limestone plays a pretty important part in the commercial capacity. Highly enriched by phosphate, limestone constitutes a major source of material for the fertilizer industry.
- When heated to a regulated temperature, limestones yield carbon dioxide and lime; lime has a special value in the production of glass and in agriculture.
- Certain varieties of limestone are also abundantly used for flooring, exterior, interior and building construction purposes.
- Although limestones are not as strong as other silicate stones hence these are highly preferred for areas with low traffic or places with less probability of abrasion. It is a popular choice for decoration purposes like wall cladding, vanity tops and paving.
- Limestones are also used in the production of glass and cement.
- Due to the high percentage of calcium, these are also used as chalk. Further of its uses is also in the making of iron in a blast furnace as it helps in the removal of impurities from the iron ore.
Dimension Stone: Limestone is often cut into blocks and slabs of specific dimensions for use in construction and in architecture. It is used for facing stone, floor tiles, stair treads, window sills, and many other purposes.
Roofing Granules: Crushed to a fine particle size, crushed limestone is used as a weather and heat-resistant coating on asphalt-impregnated shingles and roofing. It is also used as a top coat on built-up roofs.
Flux Stone: Crushed limestone is used in smelting and other metal refining processes. In the heat of smelting, limestone combines with impurities and can be removed from the process as a slag.
Portland Cement: Limestone is heated in a kiln with shale, sand, and other materials and ground to a powder that will harden after being mixed with water.
The most common variety of limestone quarried in India is that of Kota stone which is mined at the Kota district of Rajasthan. Some popular colors are blue, green, brown and pink. Other available color options are grey, black and beige as well. Although polishing can bring a smooth shine to the stone, maintenance is necessary to keep the stone intact. Limestone is not only tough but these are also a highly favored choice for their affordable prices.