Natural Granite

Natural Granite Close Up

Natural Granite Information

Natural granite is seen all over the world in a number of architectural projects. It is a visually diverse material that offers a number of benefits including durability and beauty. In this post we will consider some natural granite information about various aspects of this marvelous natural stone. Along the way we will look at some of the qualities of this stone, why it has become a standard in architecture, and how to care for it. Let’s look at our natural granite information.

Don’t Take This Stone for “Granite”

Natural granite is a stone that is used for various applications and in various environments. Like another popular and ubiquitous stone, natural marble, granite is a material that sometimes can get overlooked because it has been used for so many purposes and for such a long period of time. Yet, there are good reasons for its popularity. Let’s consider some facts about this often overlooked material.

Geological Classification

Granite is classified geologically as an igneous rock with grains that can be seen without the use of magnification equipment. Natural granite is made up of a handful of of minerals, but usually mainly contains quartz and feldspar. Granite can have a variety of appearances based on the type and colors of the minerals it contains. The classification of natural granite tells us a bit about the material, but let’s take a deeper look at this prolific natural building material.

Characteristics of Natural Granite

As stated above, natural granite forms in a variety of colors. It also offers strength and durability. Granite’s durability stems from the fact that it is a very hard surface. Thus, the stone is strong and is a material that can be versatile and unique.

The term “granite” also refers to materials that are not actually granite in the geological sense. In fact, being familiar with the term and how it is used is very important. We won’t go into all the details of the word’s usage in this post. Rather, we will stick with the properties and characteristics that make natural granite so practical and desirable.

Granite’s Composition

Granite is composed of a mixture of compounds that contribute to its properties. For example, we have already stated that the main part of the stone consists of quartz and feldspar. There are also other materials that can be present in the stone. The chemical composition of natural granite can includes:

  • SiO2 (Silica)
  • Al2O3 (Alumina)
  • K2O (Potassium Oxide)
  • Na2O (Sodium Oxide)
  • CaO (Calcium Oxide)
  • FeO (Ferrous Oxide)
  • Fe2O3 (Ferric Oxide)
  • MgO (Magnesium Oxide)
  • TiO2 (Titanium Oxide)
  • P2O5 (Phosphorus Pentoxide)
  • MnO (Manganese Oxide)

That list is not meant to be a complete list of every compound that is present in granite. Instead, it serves to show how diverse the composition of natural granite can be. Since natural granite can contain so many different compounds, it is easy to see how so many variations can exist.

Color Availability of Granite

Like other natural materials, granite gets its color from the substances that it contains. The following table shows some of the more common substances that contribute to the color of a particular granite slab:

Granite’s Substances Produce A Variety of Colors
Quartz generally appears in natural stone as a white color.
Feldspar usually shows up as an off-white color in the stone.
Potassium Feldspar revealed in granite as a pink color (salmon pink).
Biotite usually makes its presence in the form of a dark brown or black color.
Muscovite this substance appears in a granite slab as a yellow or metallic gold.
Amphibole dark greens and black colors are a result of this substance.

So in the end, the color of a granite material is dependent on the substances of which it is composed. A variety of substances results in a variety of color. The text is also influenced by the stone’s composition. Yet, the inherent appearance of a granite slab can be enhanced by the type of finish it receives.

Natural Granite Information – Finishes

There are a number of finishes that can be applied to natural granite. Additionally, the type of finish affects the appearance of the stone. Let’s briefly consider a few of these granite finishes.

Polished

A polished finish produces a glossy surface on the slab. This shiny finish has less absorbency than an unfinished stone. That translates into some benefits that we will discuss later in the post. A polished finish is accomplished by using a series of polishing pads to remove some of the granite from the surface. As a result, the granite has a very smooth gloss stone surface that appears shiny.

Honed

A honed finish is achieved in a manner similar to that of a polished finish except for the end result is a non-shiny looking surface. So, the appearance of the granite is what people describe using a variety of terms. words like “matte”, “satin”, “soft”, and “dull” are often used to describe a honed finish on granite. A honed finish alters the color of the stone somewhat.

Leathered

Sometimes referred to as a “brushed” finish, leathered granite is created by adding a step to a honed surface. A series of brushes are used on the surface of the stone. As a result, these brushes add a more pronounced “texture” to the granite. Additionally, a leathered finish retains the natural colors better than a honed surface does.

Flamed

Another way to create a unique appearance on a granite surface is to expose it to a heat source. A flamed granite finish is one such method. By using a high temperature flame on the stone, most of its carbon content is burned. Other substances in the granite are slightly discolored so their appearance is altered somewhat.

Sandblasted

When granite is struck using sand propelled from a machine, the result is a rough finish. Sandblasters are designed to force the particles through a type of “sprayer” at a high rate of speed, the result is a distinct looking finish with texture. And since sandblasting can result in breathing silica dust, it is important to make use of dust collection equipment designed for various materials. Using the proper dust collectors will enhance the safety of the job.

There are other finishes that can be used for natural granite surfaces. These are just a few of the popular ones.

Should Granite Be Sealed

One of the frequently asked questions when it comes to using natural granite is, “does granite need to be sealed?” The answer to that question will depend on some other things. For example, if the granite surface was just installed and it has received its initial seal from the installer then the answer is “not right away”. Generally a stone surface is sealed at the time of its installation. What about over time? Will granite need repeated sealing?

Depending on the type of finish and the porosity of the stone, some granite surfaces need to be sealed more frequently than do others. The more porous the material, the more sealing it will require. And even though sealers do not make the stone impenetrable, they do increase the stone’s resistance to stain-causing liquids.

Polished finishes on granite have a tendency to require less frequent sealing than do surfaces with other finishes. This is because polishing granite closes up the pores of the stone; making it less absorbent.

Caring for & Maintaining Granite

When it comes to caring for natural granite, there are a few things to consider. For instance, having a good “maintenance routine” is important. In fact, a maintenance routine is a regular practice that works to keep the stone in optimal condition. Furthermore, a good routine consists of a few practices.

The first practice needed in a good stone maintenance routine is sealing the stone regularly to maintain its repellent properties. As mentioned above, the stone will have a sealer applied to it directly after it is installed. Over the course of time though, stone sealers wear away and must be reapplied periodically. How often, depends on the stone itself and the specific sealer used.

Granite’s Uses

The versatility of granite means that it can be used for a number of applications. Many projects make use of natural granite because of its durability and timeless appearance. Some of the following applications are examples of how granite has been used as a surface material and otherwise:

  • Flooring
  • Vanities
  • Walkways
  • Cladding
  • Worktops
  • Sculptures
  • Staircases
  • Countertops
  • Building Facades

As we have seen, natural granite is a material that is popular because of its natural beauty, versatility, and diversity of colors. Additionally, it is used in all sorts of environments and in conjunction with many other materials. Furthermore, natural granite surfaces have proven to be an effective material for architectural projects, design projects, and residential kitchens. So there is no doubt it will continue to be used in large and small projects for many, many years to come.

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