Stone Discoloration

Discoloration On Stone Surfaces

Hard surfaces are available in a variety of materials. In fact, there are many man made materials that are referred to as “stone” for various reasons. Furthermore, even materials like ceramic tile and porcelain countertops are often classified as “stone” products. Each of these materials can become discolored from various substances. In this article we will take a look at some of the various materials that get grouped with stone surfaces. Then, we will tour some of the things that can discolor hard materials. So let’s get into looking at discoloration on stone surfaces.

Types of “Stone”

In the world of stone surfaces, there are 3 basic material groups. These are:

  • Natural Stone
  • Engineered Stone (Quartz)
  • Sintered Stone Materialss

Discolorations On Stone Surfaces

Natural Stone

The first classification of hard materials is natural stone. Natural stone surfaces are made up of material that forms naturally in the earth. Natural stone is cut right out of a mountain side and then sliced into slabs for use as kitchen and bathroom countertops as well as other surfaces. There are many kinds of natural stone including:

  • Granite
  • Marble
  • Limestone
  • Travertine
  • Onyx
  • Quartzite
  • Sandstone
  • Slate
  • Soapstone

As you can see from that list, there is a pretty good number of natural stone materials used for hard surfaces. Yet, this is not the only group materials that fit into the “stone” group.

Engineered Quartz (A.K.A. Engineered Stone)

The second material classification we will consider in this article is engineered stone. Also referred to as engineered quartz, or simply “quartz”, this material is a man made material that is composed of a variety of substances and formed into a slab or sheet that is then used for fabricating countertops as well as floor and wall tiles.

Engineered quartz is viewed as a “stone” material by some because of the high amount of the natural mineral quartz it contains. Although quartz surfaces contain resin binders and pigments, they are considered stone by many. The quartz (a mineral found in many natural stones) content is the cause for its being viewed as a stone material.

Sintered Stone Surfaces

There is one other group of materials that are lumped into the “stone” category by some in the industry. This group is sintered stone. Like quartz surfaces mentioned above, sintered stone is a man made material. And like the previous group of materials, it is viewed as “stone” by some. Why is that the case?

Sintered stone is sold under many labels. But the most generic term of the group is “sintered stone”. This is a term packed with meaning. Sintering is the name of a process through which particles are transformed into another substance. says the following about sintering:

Sintering or Frittage is the process of compacting and forming a solid mass of material by heat or pressure without melting it to the point of liquefaction.

Because materials that are classified as sintered stone are the result of sintering particles of minerals that occur in natural stone, and the sintering process is how natural metamorphic rock forms, some view man made materials produced this way as stone materials. Some sintered stone brands include:

  • Lapitec
  • DuraLosa
  • Neolith

Other Sintered Materials

There are other materials that are produced using the sintering process which are not viewed as “stone” and yet they are frequently worked and fabricated using the same tools. In fact, even though they are not considered stone, they are usually described and grouped with natural and engineered stone materials. These are porcelain and ceramic. Porcelain countertops have recently been growing in popularity and ceramic and porcelain flooring have been used for years as flooring and wall tiles.

Commonalities Found In Stone Products

As we alluded to above, all of the materials that we have considered thus far are worked using some of the same tools. For example, each of these groups have materials considered to be “hard” stone. So the same diamond bridge saw blade for quartz is sold as a grnaite blade as well. These are marketed as hard stone blades because of this fact.

Types of Stone Discolorations

Now that we have covered the various classifications of what many consider to be “stone” materials, we can begin exploring the many kinds of discolorations on stone surfaces. We will not cover every single discoloration for each material, but we will do our best to be as thorough as we can by talking about groups of materials.

Stains In Natural Stone Pores

One of the features of natural stone that sintered stone and engineered stone groups do not have is porosity. Pores in natural stone materials allow for the first kind of stone discoloration that we will talk about; staining. Stains are discolorations inside the pores of natural stone surfaces. When a colored liquid makes its way into the pores of a natural stone, it leaves a discoloration inside the pores after the water evaporates. These discolorations require specific stain removers designed for whichever type of substance left the stain. Some of them include:

  • Oil and Water Based Stains
  • Rust Stains

Discolorations In Calcareous Natural Stone

In the case of natural stone that is calcareous, there is also another type of discoloration called etching. What are calcareous stones? Simply put, a calcareous stone is one that is largely made up of calcium carbonate. Some calcareous stones are:

  • Marble
  • Travertine
  • Limestone
  • Onyx

Etching occurs when an acidic liquid comes into contact with the calcium carbonate. The acid reacts with the calcite and dissolves it. The result is a discoloration. The discoloration on stone surfaces that are calcareous will be in the form of a dull spot on polished surfaces. In the case of honed surfaces though, it will appear as a dark spot on the surface.

Surface Discolorations

Unlike natural stone, sintered materials do not have pores into which liquids travel. So everything that contact s quartz, sintered stone, porcelain, and ceramic panels or slabs stays on the surface. What does that mean that these do not stain? No. Even though the substance remains on the surface does not mean it cannot stain these materials, it just happens differently.

Surface stains on engineered quartz and sintered materials result from a liquid drying on the surface or chemically reacting with it. There are many substances that can dry and cause discoloration on these surfaces. Some of them include:

  • Nail Polish
  • Tar
  • Nicotine
  • Lipstick
  • Wine
  • Rubber
  • Cement
  • Mineral Deposits
  • Candle Wax
  • Grease
  • Oil
  • Rust
  • Ice Cream
  • Coffee
  • Pencil
  • Blood
  • Ink
  • Permanent Marker
  • Metal Marks
  • Chewing Gum

The above substances are cleaned up using various cleaners; each designed for a sepecific kind of substance. One of the most common kinds of discoloration on surfaces is mineral deposits – or limescale. Acidic cleaners work well on mineral deposits. It is always recommended to read and follow the instructions for the material and/or the cleaner used for treating discolorations on stone surfaces.

As we have seen in this article, there are a number of materials that get classified as “stone” and there are a number of ways that each of them can become discolored. Yet, getting a discoloration on a stone surface, no matter which surface or discoloration, there is probably a cleaner or remover to repair the surface.

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