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Natural Limestone

It's a material that gets less recognition than other natural stone choices. However, natural limestone is a choice that is a good fit for a variety of uses. Knowing a little bit about this material will enable you to make a determination regarding its use in specific projects you take on. In this article we will cover the basics regarding natural limestone and some specific uses for which it is a good fit. We will also look at some basics about working with natural limestone and how it can be cared for.

Why People Choose Limestone

One of the reasons limestone is selected for projects is because it has a tendency to be a light, neutral color that is well-suited for complimenting many other colors and materials. So it can be easily incorporated into designs of all sorts.

Another reason limestone makes the grade for projects is because it is a material that naturally fits into wet environments. We won't get into the reasons for that right now, but often times you find limestone used in places where there is great deal of water.

Limestone's Properties

Natural limestone is a sedimentary stone that forms in oceanic environments. Because of this, the material often contains remains of aquatic life that has fossilized. Note what Wikipedia says regarding this:

"Limestone is a common type of carbonate sedimentary rock. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO 3). Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes have likely been more important for the last 540 million years. Limestone often contains fossils, and these provide scientists with information on ancient environments and on the evolution of life."

Because of the way the material forms, it contains a great deal of calcium carbonate. Limestone is also similar to other natural stone materials such as travertine, onyx, and marble. The similarities stem from the fact that all of those materials are in the group called "calcareous". The calcareous nature of limestone means that it ahs certain characteristics. Let's consider some of those now.

Natural Limestone is A "Soft" Stone

The high calcium carbonate content of limestone means that it is a "soft" stone. On the Mohs scale of mineral hardness, natural limestone comes in at around 3 to 4. The Mohs scale ranges from 1 to 10 with 10 being the hardest. So, limestone and the other calcareous materials mentioned earlier are on the low end of that scale. Below is a representation of the Mohs scale.

Mohs Scale of Mineral Hardness
Mineral Hardness Limestone Note
Talc 1 Talc is a mineral that is the primary part of talcum powder.
Gypsum 2 Formed when seawater evaporates from the surface of the Earth. It is also found in drywall.
Calcite 3 A carbonate mineral found in many popular stones such as marble and limestone. It is often the primary constituent of the shells of marine organisms.
Fluorite 4 The mineral form of calcium fluoride. It is often used for ornamental carvings.
Apatite 5 A group of phosphate minerals named by the German geologist Abraham Gottlob Werner.
Feldspar 6 Feldspars are a group of rock-forming tectosilicate minerals that make up about 41% of the Earth's continental crust by weight.
Quartz 7 A hard, crystalline mineral composed of silicon and oxygen atoms which belongs to the trigonal crystal system.
Topaz 8 Topaz is a silicate mineral of aluminum and fluorine. In its natural state, Topaz is golden brown to yellow in color.
Corundum 9 Corundum occurs as a mineral in mica schist, gneiss, and some marbles in metamorphic terranes.
Diamond 10 Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic.

Limestone Is Usually A Light Color

Another property of limestone is that it is light in color. Again, this is because limestone is primarily made of calcite, a light colored substance. Although other minerals and substances also can be in the stone and add other colors to it.

Limestone Is Water Friendly

In addition to being soft as far as stone is concerned, and light in color, limestone also performs well in environments where there is water. When you think about it, that makes sense. After all, the material itself forms in the presence of water. So it is not a big surprise that natural limestone seems to be a perfect surface for use as shower tiles or pool decking. Additionally, limestone is prous and absorbs water well so that wet surfaces do not get as slick as other materials do when it gets wet.

Working With Limestone

Fabricating natural limestone is much like working with other materials. There is specific equipment that is used to cut, shpae and otherwise work with this natural stone. One area that is good to consider is cutting. Much like its close natural stone relatives, limestone is best cut using a diamond blade made for cutting soft stone.

Just like some diamond blades are made for working with softer stone, there are diamond polishing pads for limestone, marble, travertine, and other soft, calcareous natural stone surfaces. Using polishing pads designed for limestone will give you quality results and produce a great polish.

Caring for Limestone

Limestone care and maintenance is relatively easy. Caring for limestone involves applying sealer to the stone to help it resist absorbing liquid that could discolor that stone if it is used as an indoor flooring material. The sealer will have instructions for how to apply and when to apply. Depending on what kind of stone sealer you choose to use, you will need to reapply regularly to the stone. Addtionally, the stone's porosity, and the amount of use will affect the frequency with which the stone will need to be sealed. Always use cleaners that are pH neutral and if your limestone gets etched, reseal the stone after removing the etch using the proper etch remover.

In summary, natural limestone is a very effective stone material that is great for specific uses. It is normally light in color and is a soft stone that cna be cut and polished using the proper equipment. Caring for limestone surfaces, like other natural stone, involves applying a stone sealer periodically. Natural limestone is not the best material for every project, but there are some uses for which natural limestone is a good fit. Being familiar with the material helps in recognizing when it is a good choice.