Limestone

Limestone is a sedimentary rock, which is composed of calcium carbonate (calcite) or the double carbonate of calcium and magnesium (dolomite) tiny fossils, shell fragments and other plants remains. It is formed over many years at the bottom of oceans or lakes from the accumulation of shells, bones and other calcium rich minerals. A limestone can metamorphose into marble, if it is subjected to intense heat or pressure, for over a long period of time. Both limestone and marble, chemically contain calcium carbonate and the only difference, one can find will be of their appearance. Marble will have a crystalline structure, whereas the limestone will have relatively flat appearance. Limestone is generally quite impervious and hard in nature.

Limestone is further sub-divided into travertine and dolomite limestone. Travertine is formed when water evaporates from the limestone caverns and dolomite limestone are those limestone that are compose of magnesium. Dolomite limestone is much harder and more resistant to weathering.

Limestones are fit for building purposes, though many of them are burnt for lime. In the Cuddapah, Bijawar, Khondalite and Aravalli groups, limestones attain considerable development, some of them being of great beauty and strength. They have been largely drawn upon in the con- struction of many of the noted monuments of the past in all parts of the country. Vindhyan limestones are extensively quarried in Rajasthan and form a source of building stone as vaiued as that of lime and cement mentioned earlier.

Limestone is an excellent building stone because it can be carved easily. It is most commonly used for flooring, wall cladding, vanity tops, furniture, and many times, ornate stonework. Apart from its application in the construction, it is also used in factories to clean waste gases and water, before releasing them into the environment. Limestone can also be used to make lime and to smelt iron ore.