In the stone industry there are a number of stone and engineered materials that have become increasingly used for countertops. However, there others that have been used for all sorts of applications for hundreds and even thousands of years. In this article we will consider granite vs marble and see how these materials compare with one another. We will also examine the similarities of these materials as well as their differences.
Comparing Granite and Marble
Granite and marble are two of the materials that have been used for architecture, surfaces, and even sculptures. Throughout history, these materials were chosen as building and sculpting materials because of their qualities.
In modern times both of these materials have been used for countertops of various sorts. But how do these materials compare to one another? Are they the same material with differing labels? As we get further into comparing granite and marble you will see the answer to those questions. We will compare the composition of these materials. Then we will explore the properties. Finally, we will expound on what the comparison means. So let’s get into looking at granite vs marble.
Natural granite is an igneous rock that forms naturally. It has a mineral content that varies slightly but it is made up of the following minerals according to Wikipedia.org:
The variations in the amounts and masses of the minerals mentioned above are what make the stone unique form every other stone. Even two slabs of granite will be different to the degree that they contain different minerals. We won’t get into the details of what this composition means int he context of granite vs marble just yet. However, the minerals in the stone play a role in the comparison as you will soon see.
Composition of Marble
Like its counterpart, marble also is a natural stone that forms in the earth. Yet it is a rock that falls under a different class and the composition is much different. Natural marble is a metamorphic rock that at one time was a different rock. Because of heat and pressure, one rock gets transformed into a different rock. Marble is one result of this process. The mineral content of natural marble is as follows according to the same source used above:
As you can see, the composition of marble is basically calcium carbonate. Depending on the context, marble may refer to metamorphosed limestone (the context of geology) or un-metamorphosed (in stone masonry). The reality though is that all marble contains calcium carbonate. This is going to translate into an important difference from granite as we will see in the next part of this article.
Properties of Granite
Exploring granite vs marble is really about considering the properties of each material and seeing how these materials perform in various applications. Namely, kitchen countertops for this discussion. The properties of granite that we will look at here are 1) hardness, 2) porosity, and 3) color.
As we mentioned earlier, granite’s composition affects its comparison with marble. How so? The properties of a stone are determined by the properities of the minerals it contains. The minerals in granite make it a hard material. Natural granite is on the high end of the hardness scale used to measure mineral hardness due to its mineral content. Because granite is hard, it is resistant to scratching and chipping; although it can be chipped or scratched.
How tightly compressed the minerals are in the stone determine how porous that stone is. In the case of granite, its porosity varies to a degree. Because there are different porosities, you will find different qualities, or grades, of granite countertops. The more porous the material, the easier it will stain if not treated with a stone sealer.
The color selection of granite is also affected by the minerals it contains. Varying minerals mean varying colors. The minerals themselves even vary in color. This means that there are a wide variety of granite colors. In fact, between the color and pattern, you will find that the appearance variations in granite are virtually limitless.
As mentioned before, the composition of a stone determines the properties of that stone. Since marble is composed of calcium carbonate, a mineral not generally found in granite, the properties of marble are different from granite. Let’s briefly consider the same three properties.
Marble is not as hard as granite. In fact, marble is considered a soft stone. On the same scale of mineral hardness mentioned earlier (the Mohs scale of mineral hardness), marble falls on the lower end of the scale. And even though marble is a natural rock, it is not as hard as other rock is. So, it scratches more easily that does granite. However, when it comes to sculpting, marble is easier to work with.
Marble, like granite will vary somewhat when it comes to the porosity. Depending on the type of marble and the context in which the marble is defined (geologic or stone masonry) the marble can vary in porosity. Like its counterpart granite, marble too needs to be sealed using a natural stone sealer to keep it from staining.
In addition to water based and oil based stains, natural marble also brings with it the susceptibility to “etching”. Etching occurs in any calcium carbonate based stone. When an acidic substance interacts with marble, the acid dissolves the calcium carbonate and leaves a noticeable mark. Polished marble looks dull and honed marble looks darkened where the acid was. Since acidic liquids breakdown stone sealers, the only way to protect a marble countertop from etching is by prevention.
For the most part, natural marble is light in color. And pure marble is nearly completely white. Non-calcitic minerals that mix with the calcium carbonate are sometimes referred to as “impurities” and these small amounts of minerals are what cause the veining in marble. Even though the colors seem limited in concept, the variations in veining patterns make marble countertops unique too.
Granite vs Marble
|Comparing Granite and Marble
|6-7 on Mohs Scale
|3-4.5 on Mohs Scale
|Scratch Resistance or Sculptibility
|Numerous (Virtually Unlimited)
|Usually Light (White is “Purest”)
As we have seen in this comparison of granite vs marble, these two materials are both natural stones. However, they are very different in composition, hardness, and appearance. Yet, they both have been used for hundreds of years. Choosing one for a countertop material will depend on what you want form your countertop and where it will be used.