Natural Stone Stain Types: Identification for Removal
Stains that occur on natural stone surfaces exist in many forms. Each type of stain brings with it a potential need for specific removal techniques, products, or both techniques and products. Therefore, we have put together this document as a reference for, not only the stain types, but also their removal. In this document, we will go through the list of stain types that most commonly affect natural stone. As we consider each, we will mention a technique and/or product that is designed to help with this type of stain.
Water Spot Stains
This may be a surprise if you have not encountered it yet. But regular old water can and does cause stains on stone. You may be thinking, "Can't I just wipe up the water?" The answer to that question is, "Yes, you can." However, there may be an accumulation of water deposits on the surface after the water is removed. This happens particularly where water is regularly present on a stone's surface. Generally, these can be cleaned using cleaner for removing water spots.
There are many substances around the home that are oil-based. These will cause dark spots on the stone. Oil-based stains are normally removed using chemicals. Examples of Oil-based stains are:
- Cooking Oil
- Olive Oil
- Salad Dressings
Another common household substance that creates stains on a natural stone is ink from writing utensils. Pens, highlighters, magic markers, and ink in general leave stains on stone surfaces. The method for removing these depends on what color the stone is.
Ink On Light Stone
To clean ink stains from a light colored natural stone surface, depending on the stone you may be able to use bleach or hydrogen peroxide, give us a call and we can help you determine what works best for your particular stain.
Dark Stone and Ink Stains
In a case where the stain is on a dark colored stone, using a mixture of acetone or lacquer thinner to remove the discoloration, please contact us to determine what will be most effective.
Stone & Organic Stains
Many substances that are derived from living things also cause stains on stone surfaces. The following are some examples:
Depending on the location of these stains (indoor or outdoor), removing them will require differing methods.
Organic Stains Indoors
When an organic stain occurs indoors, you will generally need to remove it using a solution that fades or bleaches the stain. Usually, cleaning organic stains indoors can be done with an organic stain remover.
Outdoor Organic Staining
The outdoor elements generally wash, fade, and bleach the stains that come from these kinds of stains once the sources have been removed. However, there are stain removers for organic stains available.
Staining from Biological Sources
What may be referred to a stain could be discoloration that is, in actuality, coming from a biological source. For example, mildew, moss, fungi, and lichen are actual living organisms that thrive in certain environments. These discoloring culprits must be eliminated using stain removal treatments that will kill the organism. There are though, cleaners for removing mold that also inhibit the regrowth of the stain-causer. Using these products is beneficial because often times the environment in which the organism grows cannot be changed. So, prevention is the recommended course.
Removing a paint stain might depend on just how large or how heavy the stain is. Small spots on a stone are easily removed using a razor blade. Additionally, you can find ceramic razor blades that work well for this since these will not leave metal marks on the surface of the stone.
Of all the stain types we are discussing, this one might be the one that is, in a sense, the most interesting. Etch marks only occur on calcareous stone. For more information on what this means, you can check out our article entitled: 2 Basic Types of Natural Stone You Should Know.
Etch marks happen when acid reacts with the mineral in some stone. This reaction leaves a dull spot or a dark spot on the stone where the acid was. Removing an etch in a stone surface means not so much removing a stain, but more of a re-balancing of the stones properties so that the discoloration is not as noticeable. To accomplish this, you can use an etch remover for calcareous stone. Using etch remover as the directions instruct restores the appearance by blending the differences in the finish so that the discoloration is no longer seen.
Stains from Fire & Smoke
A significant number of fireplace surrounds and hearths are made of natural stone. Smoke and fire will stain natural stone surfaces and restoring a smoke and fire stained fireplace requires thorough cleaning using commercial products.
Depending on where a stone surface is, sometimes water can move through the stone from bottom to top. As the water passes through the stone, it can carry mineral salts from below the stone up to the top. After the water evaporates from the surface, it leaves a white powdery substance behind. This is called efflorescence. New installs can be cleaned by simply vacuuming up the powder repeatedly until the process stops when the stone dries out. However, re-occurrence may require the source of the water to be removed; after which the efflorescence will stop.
Inorganic Metal Staining
Some stains happen from the contact of metal with the stone's surface. Not only can stone receive metal marks from direct contact, but there also reactions resulting from environmental factors and metal being in the presence of stone. Some metals that can discolor stone include:
Metal stains must be removed using a poultice powder. There are some stains that are incredibly difficult to remove. For example, some deep-seated rust stains may permanently stain the stone, but might be able to be lightened by using special techniques and cleaners.
Stain Identification & Removal Reference
Since there are so many types of stains, we have put together a handy reference for identifying stains. Once the type of stain is identified, the appropriate method(s) and/or product(s) may be used to treat the particular stian needing removed.