Limestone has low porosity; it is weather resistant and has a density of between 2.5 and 2.7 kg/cm3. It has a hardness of between 3 and 4 on Moh's Scale and a water absorption of less than 1 percent.
Limestone is a very compact rock that takes polish very well. It is a sedimentary rock that is usually formed at the bottom of lakes and oceans and is calcium-rich. Its chemical formula is CaCO3 and it is where many fossils are found. Calcium carbonate is limestone that contains at least 95 percent calcium and magnesium limestone is limestone in which some of the calcium has been replaced with magnesium.
Limestone is an acid sensitive stone, similar to marble. It is often used on the floors of homes and businesses and also used to make counter tops, furniture, chalk and in cement production.
Limestone has many chemical properties as well as physical properties. It contains between 38 and 42 percent lime, 15 to 18 percent silica, three and five percent alumina and trace amounts of magnesium oxide and iron oxide.
In the U.S., limestone occurs in the Lampasas River area of Texas. It can also be found in the UK in England, and in the Airedale Road Weston region of New Zealand.