73 Limestone Facts For Kids To Learn About The Sedimentary Rock

Depending on the hardness of the rock, limestone is extracted either by blasting or mechanical excavation.

The crushed stone is sorted into different fractions by screening and further processing. The limestone is ground into a finely powdered limestone during the grinding process.

Want to know more about this rock? Proceed further to learn more facts in this article.

Properties Of Limestone

Limestones are the most important sediment rocks per the Sedimentary Rocks Mineralogy and Classification. Limestone is quite a fascinating rock, and we have compiled some of the facts, characteristics, and properties of limestone for your ready information.

A significant portion of Earth's crust constitutes limestone and marble, and these minerals contain calcite.

Limestone is essentially one of the most common natural materials and has unique properties.

Calcium carbonate found in limestone is also used as a dietary supplement for healthy bones, muscles, nervous system, and heart.

While maintaining the inherent characteristics of limestone nowadays, a cost-effective alternative to natural limestone is also available in the market manufactured through a milling machine process.

The scientific name of limestone is calcium carbonate (CaCo3) in the mineral form calcite or aragonite.

The chemical purity of limestone can range from only 80-90% calcium carbonate to over 99.9% purity.

Limestone is often associated with essential carbonate minerals and contains variables of silica, clay, chalk, silt, sand, feldspar, pyrite, quartz, and considerable amounts of magnesium carbonate (dolomite).

Most of the limestone forming environment is found in shallow water areas between 30 degrees north and 30 degrees south latitude.

These stones are found in the Caribbean Sea, Persian Gulf, Indian Ocean, Gulf of Mexico, Pacific Ocean islands, and the Indonesian archipelago.

Limestone is usually white and is found colored by impurities.

Limestone layers contain sand, organic remains, and iron oxide that can make the limestone red, yellow or brown, and the carbon content can make it grey, blue, or black.

Depending on the limestone formation, they can be either clastic, granular, crystalline, or dense.

The barite or dolomite, quartz, or calcite crystals may line small cavities in the limestone rock.

Limestones are the root of many crystals, including agate, dolomite, calcite, and septarian.

Most of the grains found in limestone are skeletal fragments of marine organisms like coral or foraminifera.

Extraclasts, intraclasts, peliods, and ooids are the other carbonate grains comprising limestone.

Limestone is a sedimentary rock having more than 50% calcium carbonate in the form of calcite by weight. It also contains some percentage of other materials as well.

The chemical composition of pure calcite is CaCO3. The limestone comprises calcite or double carbonate consisting of calcium and magnesium (dolomite).

Limestone is a material that is non-hazard as it is not combustible or flammable; however, it may rupture containers if it reacts with incompatible materials such as acids.

The limestone is a natural sedimentary rock formed from coral, algal, and fecal accumulation and includes many fossils and tiny fossilized organic debris and shell fragments.

Limestones can also form by chemical sedimentary processes like precipitation of calcium carbonate from lakes or ocean water.

These stones form amazing caves for the public to explore and are comparatively a harder grey limestone rock formed millions of years ago.

The groundwater deposits the secondary calcite in caves described as travertine.

The groundwater or the rainwater that seeps through and is found in caves precipitates into minerals built up after innumerable water drops known as the stalactite, which contains dissolved calcite.

The groundwater of the rainwater that seeps and drops from the top of the cave is stalagmite, which contains dissolved calcite.

The stalagmite and stalactite are speleothems produced in caves formed at varying rates as calcite crystals build up and are found in limestone caves.

The limestone is divided into low magnesium and high magnesium, and the dividing line is placed at a composition of four percent.

Most of the grains of a limestone range in size from 0.00004 in (0.001 mm) to visible particles; hence the texture of the limestone is granular and clastic or non-clastic.

Compared to sandstone, the limestone tends to be flatter and smoother, with fewer ridges in its finish.

Limestone is slightly soluble in water but more in acid and can thus speed the dissolution of limestone.

Limestone rock is comparatively soft and is easily scratchable, and will produce a vigorous fizz in any common acid like hydrochloric acid.

Carbon dioxide gas is caused due to limestone fizzing after it reacts with acidic solutions.

All metal carbonates calcium carbonate reacts with acidic solutions and produces carbon dioxide gas caused due to limestone fizzing. 

The hardness scale recorded on a Mohs scale of limestone is between three and four.

The crushing strength of dense limestone can be up to 180 MPa. For the understanding purpose, the typical crushing strength of concrete is about 40 MPa.

Limestone is very soluble, dissolves the stone over a period of time, and also becomes more porous due to exposure to other elements. Hence the porosity of limestone is relatively low.

The water absorption of untreated limestone is 11.69%, and the water absorption of treated limestone is 3.023% with Oxal NK100 stone stabilizing compound.

As the water flows through sedimentary rocks, it picks up minerals from rivers and lakes. While limestone and dolomite dissolve in water, half is the carbonate (alkaline), and the other half of the molecule is calcium or magnesium (hardness).

When limestone meets with weakly acidic rainwater, some calcium carbonates react to form a calcium bicarbonate solution.

Uses Of Limestone

Scientifically there is great importance for the limestone because it provides an insight into the geological period of the fossils it contains. It enables scientists to find when and under what environmental conditions limestone was formed. Here are listed interesting features and uses of the limestones.

Limestones are commonly found in holes formed due to natural depression on the Earth's surface, which are also called sinkholes or swallow holes.

These holes are caused when a roof of an underground cavern collapses or when joints or fissures in limestone rock are enlarged by carbonation. The river or stream may suddenly vanish down a sinkhole and flow underground.

One such limestone feature is found in China and is known as the Xiaozhai Tiankeng.

Caves are naturally created underground hollows or passages, particularly those with an opening on the surface of the Earth. These caves are found in limestone areas and caused as the water dissolves the rock, making way for tunnels and even large caverns.

Several such limestone feature caves are found in Barbados, and the most famous is Harrison's cave.

Karst landscapes are distinctive landscapes of limestone areas. These landscapes are created due to chemical weathering processes of solution and carbonation.

One of the well-known karst landscapes is found in the Caribbean islands at Cockpit County in Jamaica.

Another such limestone feature is the formation of a pillar or column which extends from the ceiling of the cave to the floor, formed due to continuous fall of water drips.

The pillar or column may have been formed when a stalagmite was formed below a stalactite while the water dripped from the top of the cave.

The limestone pillar feature is found in the famous Cango caves in South Africa.

The limestones are most commonly used in construction and as building material; quarried limestone is sliced into slabs or blocks of predetermined sizes based on the requirements.

The 'Aglime,' also known as agriculture lime, includes Calcium carbonate and neutralizes acidic soils.

These stones are used in the steel industry to remove impurities from steel metals.

Crushed limestone has a cleansing and purifying property, treats wastewater, and is used in sewage systems.

These stones are used in manufacturing portland Cement used to construct houses.

These limestones are used as animal supplements for hens to lay firm shell eggs and boost the calcium level of dairy cows and chickens.

The primary raw material used for manufacturing calcium oxide is the limestones.

Calcium oxide is also known as quicklime and is used in the making of porcelain, grass and is also used for purification purposes.

Limestones increase soil's bacterial activity and create a good soil structure in a lawn.

These limestones are used to manufacture toothpaste and are used as a white pigment and filler.

Calcium carbonate, a soft compound, is used to carve and make beautiful statues. 

Limestone is used to restore the essential mineral levels and increase the alkaline levels of pure water; hence, limestone is usually added to pipes that carry purified water.

Putting grass is a special kind of grass designed to be used on golf grounds that survive at specific soil pH levels, and an application of limestone maintains an ideal pH level.

Limestone is added to these waters to protect manufactured freshwater lakes from vulnerable acidic rains and serves as a pH buffering agent.

The high resistance quality of asphalt roofing shingles sustains heat and harsh weather conditions due to crushed limestone used during surface coating.

Types Of Limestone

Limestones are sedimentary rocks formed due to millions of years ago's physical and chemical processes. There are different types of limestones and consist of a wide range available in nature.

Travertine is a durable and dense banded limestone rock composed of calcite formed due to the evaporation of river and spring waters and is found in a variety of light color limestones.

Tufa, also called calcareous tufa, is high magnesium calcite formed during the precipitation of carbonate minerals at an ambient water temperature.

Chalk is a form of limestone that includes mineral calcite formed under the sea from the compression of the microscopic plankton settled on the seafloor and is soft, white, and porous.

Shell fragments within a fine-grained matrix form coquina limestone.

It is an accumulation of sediments formed by the deposition of mineral or organic particles on the floor of oceans or water bodies at the Earth's surface.

Coquinite limestone is a consolidated and more robust version of coquina.

Oolitic limestone is calcite cemented calcareous formed of shell fragments and is non-crystalline, and is exceptionally uniform in composition and texture.

Fossiliferous limestone is made of minerals aragonite and calcite and contains many fossils or fossil traces.

Black limestone is usually rich in organic matter, and sodium and potassium oxide traces cause the black color.