How Limestone is Formed

Have you ever wondered how limestone is formed and it’s uses…
 Limestone is a type of sedimentary rocks that primarily comprise of calcium carbonate as mineral calcite. In most cases, it appears in warm, clear, shallow, marine waters. This organic sedimentary rock usually forms from the accumulation of coral, shell, fecal, as well as alga debris. It can also be a chemically formed sedimentary rock, which forms through the precipitation of the calcium carbonate from ocean or lake water.
Most limestone usually form in places where the environment has organisms that are capable of forming calcium carbonate skeletons and shells that easily extract the ingredients they need from the ocean water. When these organisms die, their skeletal and shell debris will accumulate as sediments and this might be lithified into limestone. In addition, their waste materials may also contribute to the mass of the sediments. The limestone formed through such sediments are called biological sedimentary rocks.
Some limestone may be formed through direct precipitation of calcium carbonate from fresh of marine water. These are called chemical sedimentary rocks. I general, they are less abundant compared to biological limestone.
Limestone can also be formed through evaporation. Cave formations such as stalagmites and stalactites (speleothems) are some of the examples of limestone that form through evaporation. Water seeping down into the caves through pores or fractures enters as droplets in the cave’s ceiling. They may evaporate before they reach the cave floor. In this case, the calcium carbonate that was absorbed in the water is deposited at the ceiling of the cave. These deposits are called stalactites. Some droplets reach the floor and then evaporate, and may grow a stalagmite upwards from the floor.
By definition, limestone is a rock that has at least 50% calcium carbonate by weight. All types of limestone have at least a few other materials in form of small particles of clay material, quartz, siderite, pyrite, feldspar, or other minerals. It could also contain some large nodules of siderite, pyrite, or chert. The amount of calcium carbonate in the limestone can be used to give limestone some properties that can be used in rock identification, as it effervesces when in contact with 5% hydrochloric acid.
Since this is a rock with a variety of uses, it could be the one used in more times than any other rocks. Most limestone is usually crushed and then used for construction purposes. In addition, it can be used for railroad ballast or road base, while in its crushed state. Regardless of how limestone is formed, it can be used as an aggregate concrete or even fired in a kiln to make cement.
However, some variety of limestone may perform better in some uses depending on how limestone is formed. This is because they are stronger, and denser with lesser pores. Such properties enable the rocks to resist abrasion as well as freeze-thaw. Powdered limestone is usually used in paint, plastics, rubber, and as filler in paper. It can also be used as a sorbent in coal burning facilities.
One more place limestone is used is in interior and exterior architectural designs. It can be used for fireplaces, columns, firepits, waterfalls, and much more. So next time you are looking for something special to make your home unique, look at limestone as an option… you will be amazed at what it can be made into.

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