Limestone vs Travertine
Whether you have heard of one or both of these materials, you may have only heard a little bit of the information. Limestone vs travertine comparisons can be very short, depending on how you you make the comparison. In this article, we will talk a little bit about each of the stones. And then we will briefly compare these two unique materials.
Summarizing what limestone is not extremely difficult. In fact it is fairly easy. Limestone is a sedimentary rock that contains fossils. It is composed of calcite and is used for a variety of applications. Here is how the U.S. General Services Administration defines limestone:
Limestone is a sedimentary rock composed principally of calcium carbonate (calcite) or the double carbonate of calcium and magnesium (dolomite). It is commonly composed of tiny fossils, shell fragments and other fossilized debris. These fossils are frequently visible to the unaided eye on close examination of the stone surface, however this is not always the case. Some varieties of limestone have an extremely fine grain.
Notice in that description of limestone that "shell fragments" were listed as part of the "fossilized debris" that is found in limestone. That is a hint to how this rock forms. Limestone forms when the minerals it is composed of precipitate out of water containing dissolved calcium. In other words, this stone forms in aquatic areas; in the ocean's floor, etc.
Like its counterpart, travertine forms in aquatic settings. In fact, travertine is a form of limestone. However, there is a distinct difference in the environment in which travertine forms. Rather than forming in ocean floors, travertine forms by means of terrestrial (land) precipitation. Terrestrial precipitation in "land" settings?
You may be thinking, "does it form on land or in water, which is it?" And the answer is, the environment travertine forms in has both. It is deposited around rivers and mineral spring waters. Think caves and hot springs and you'll be in the right kind of area. Now we could end this article right here and imply that the two are are the same and have the same properties, but we won't. They are actually two different stones with differing properties we will get to in a bit. First though we want to talk a little about what they have in common.
Characteristics of Limestone
Limestone is composed largely of calcium carbonate material. Because of this, limestone is generally light in color. It is usually gray but can also be white, yellow, or brown in hue. Because of the large amount of calcite in the rock, it is what is referred to as a "soft" rock. That means it is easy to scratch. The Mohs scale of mineral hardness is a scale from 1 to 10 (softest to hardest) and limestone generally ranges from 3 to 4. so it lives at the soft end of the scale. However, it is stone so it is usually referred to as a "relatively" soft stone. Like virtually all natural stone, it is porous and each stone's porosity varies a bit. Some limestone is more porous than other and the best way to determine the porosity of a given stone is to perform a water test (a.k.a. absorption test). Moreover, using a quality stone sealer on the surface significantly reduces the absorption and keeps water-based and oil-based liquids on the surface.
Traits of Travertine
The traits of travertine are much like those just mentioned. Travertine is generally light in color, usually gray, brown, or yellowish in color, and is soft because of its mineral content. it has a hardness of around 4 to 5 on the Mohs scale so, it is also on the soft end of the spectrum. Again, so far it sounds like this stone is basically the same thing as its counterpart. Yet, look at how these materials compare.
Travertine and Limestone Compared
All things considered, these two materials are very much alike. After all, one is a specific type of the other. They are composed of the same main mineral (calcium carbonate) and they share some visual characteristics too. But the way these rocks form creates in them differences that are detectable and can be seen with the naked eye. Just because two substances are made up of the same thing doesn't mean that they look alike. For example, sleet and snow are made up of the same thing. They are both frozen water. Yet, they look very different from one another and their is a distinction between them. So let's look the similarities between limestone and travertine and then we will consider how they differ.
Travertine and Limestone Similarities
From what we have covered up to this point, you can readily see the similarities between limestone and travertine. Both of them are relatively soft stone. (Although travertine's range of hardness is just a hair harder.) Both are mainly calcium carbonate, which has the same influence on the color spectrum of each material. Their calcite content also means that both of these materials will etch in the presence of acids. Common acidic liquids will react with the calcium carbonate and dissolve it, leaving a discoloration of one sort or another.
Differences Between Limestone and Travertine
Now we have come to the part where we actually differentiate between these two materials in the visual aspect. Limestone often contains fossils. Remember earlier we said that limestone forms on the ocean's floors? Well what happens to marine life when it dies? Where does it go? On the other hand, we said that travertine forms where there is air and water. And that leads us to the distinctive visual characteristic that marks travertine.
Travertine is a "cellular" stone. It forms with voids (also called pits, holes, pockets, cells, etc.) throughout the material. When the stone is cut these holes are visible. When travertine is processed the cells are removed by filling them using filler for travertine. This leaves the surface of the stone smooth to the touch. Depending on whether the travertine filler used was a complimentary color or transparent, you will either see a two-toned pattern with the stone portion being one color and the filled holes the other, or you will still see the holes, they will just be filled in. Either way, the look of travertine is very distinct and once you have seen it, you can recognized most travertine relatively easily.
As we have seen in this article, two materials composed of the same minerals can look very different in the end. Yes travertine is a specific kind of limestone, but it looks very different, is generally slightly harder than non-travertine limestone and is usually filled during processing. Yet, both of these materials are used for surfaces through interiors and exteriors of homes and businesses.