Category: Articles

Fabricators and restoration contractors often get calls about cracks in natural stone countertops. Sometimes these “cracks” are not cracks at all, but fissures, a feature of the stone that resembles a crack. How does one go about determining whether a countertop has a fissure or a crack? It all boils down to observation.

Naturally Occurring Versus Human Intervention

Fissures are a result of naturally occurring phenomenon, such as geological and environmental forces, crystallization of minerals, and other conditions. Cracks are a result of man-made stresses, such as transport from the quarry to the fabricator or from fabricator to a residence or commercial facility. Man-made stresses may also happen during the installation process.

Visual Differences

Knowing what to look for can help with determining whether you are dealing with a fissure or a crack. Fissures are elongated but extremely narrow openings along the boundaries of crystalline structures in the stone. The visible separation usually remains within the depth of the stone, although it sometimes can go entirely through. Fissures often appear in more than one place on the slab and are rarely straight. Cracks can be narrow or wide, usually only appear in one place on the slab, and may go through the entire depth of the stone. Cracks caused by stresses during the installation process are commonly observed in straight lines near supporting structures.

Tactile Differences

Knowing how a crack or fissure feels when you run your fingernail across the surface of the stone can help you determine whether you are dealing with a fissure or a crack. Your fingernail will run smoothly over a fissure, because a fissure does not change the plane of the stone, and it does not cause any gaps or depressions in the stone. However, your fingernail will not run smoothly over a crack. There will be noticeable unevenness, as one side of the crack is often higher than the other side. In other words, a crack can change the plane of the stone, and your fingernail will catch on the difference.

From Fissure to Crack

A fissure is not a crack, and although fissures rarely affect the soundness of the stone, sometimes a fissure can develop into a crack. You will know if this happens because there will be some chipping, separation, and obvious breakage.

What To Do About Fissures and Cracks

Fissures are naturally occurring and add to the character of stone. As such, nothing at all should be done about them. Some people who purchase quartz, onyx, or other translucent stones under-light them to bring attention to fissures and other natural features. Cracks, on the other hand, are structural defects that can worsen over time and may harbor bacteria and contaminants. Cracks should be repaired by a trained and qualified stone restoration contractor who can determine whether underlying structural repairs are needed and match the repair site as closely as possible with the surrounding stone.

A question our clients frequently ask is, “How can I remove water rings on my polished marble?” This article explains what “water rings” are, and what you can do about them.

Cause of Water Rings

Polished marble ideally has a glossy, glass-like, reflective finish. “Water rings,” although seemingly insignificant, can really diminish the appearance of polished marble when the lighting is just right. Blemishes on polished marble or other natural stone that are commonly mistaken and referred to as water rings are generally etch marks. Etching is chemical surface damage caused by acidic or high alkaline substances.

Removing Water Rings

If the etching is mild, that is, if you can run your finger across the surface of the stone and the finish still feels smooth, then you should be able to use a high-quality marble polishing compound to remove the etch.

Professional Services May Be Necessary

If the etching is severe, that is, if you run your finger across the surface of the stone and the finish feels rough, then the etch should be removed by a professional stone restoration contractor. Attempting to remove a severe etch on your own could result in further damage to the surface of the stone.

How to Prevent Water Rings

What can you do to prevent etch damage? Use drink coasters. Clean up spills immediately. On marble kitchen countertops, don’t store wine bottles, vinegar bottles, or similar items directly on the stone, and on marble vanity tops, don’t store cosmetic products directly on the stone. Instead, use trays to store items on your tops.

Contrary to what you may have heard, marble sealers cannot prevent etch damage. Sealers penetrate the surface of the stone to inhibit liquids from being absorbed into the stone. Acidic and high alkaline substances don’t need to be absorbed into the stone to cause damage, they merely have to come into contact with the stone. There are, however, some new solutions on the market to prevent etching on countertops and vanity tops.

Feel free to contact us for specific etch removal product recommendations, to learn more about etch prevention solutions, or to schedule professional etch removal services.

Alkaline Can Etch Natural Stone

Many people who own marble countertops, floors, or other surfaces are aware that acidic substances like vinegar, lemon, tomato, etc. can cause etching on natural stone, but did you know that substances that are high in alkaline can also cause etching?

About Alkaline Etch Damage

Liquid Plumber, alkaline strippers, ammonia, and heavy duty stone cleaners can cause alkaline etch damage on natural stone because of a chemical reaction in which alkaline salts are deposited into the surface of the stone. An alkaline etch mark is similar in appearance to an acid etch mark.

A persistent white spot on a glass from your dishwasher is an example of an alkaline etch. Dishwashing detergents tend to be high in alkaline, and if your rinse cycle is not thorough enough, the alkaline causes chemical damage to the surface of the glass. That is why the spot does not disappear when you dry it with a towel. Similarly, high alkaline substances cause etch damage on natural stone, and such damage cannot simply be wiped or cleaned away.

Removing Alkaline Etch Marks

If your natural stone is something other than polished marble, you may attempt to remove a moderate alkaline etch mark using a mild acid. Be sure to thoroughly rinse the area to avoid causing acid etch damage to the stone. Re-honing and re-polishing may be necessary. Please feel free to contact us with questions or concerns you have about alkaline etch damage.

Natural Stone Stains Can Be Removed

The key to successfully treating natural stone stains is cleaning up any spills and treating any resulting stains as soon as you can. The best way to remove a stain on stone or other porous hard surfaces is with a poultice. A poultice is simply a mixture of a chemical or cleaning agent to break down the stain and an absorbent material to draw the stain out of the pores of the stone. You can purchase convenient ready-made poultices or create your own.

Before you attempt to remove a stain, be aware that a stain is a discoloration, but not all discolorations are stains.

A true stain is always darker than the stained material. If it appears as a lighter color it is not a stain, but either a mark of corrosion (etching) made by an acid, or a caustic mark (bleaching) made by a strong base (alkali). In other words, a lighter color “stain” is always surface damage and has no relation whatsoever with the absorbency rate of the damaged material—stone or otherwise. There is not a single exception to this rule.

Stone Stain Removal: The Poulticing Method

As mentioned above, a poultice is the combination of a very absorbent medium (it must be more absorbent than the stone) mixed with a chemical, which is to be selected in accordance with the type of stain to be removed. The concept is to re-absorb the stain out of the stone. The chemical will attack the stain inside the stone, and the absorbent agent will pull them both out together. The absorbent agent can be the same all the time, regardless of the nature of the stain to be removed, but the chemical will be different—in accordance with the nature of the staining agent—since it will have to interact with it.

Please feel free to contact us with any questions you may have about removing a stain from your natural stone.

Can you use limestone in a shower?

Natural stone showers, whether tub-surround or walk-in, play an important role in bathroom design and function. Stone selections vary by color, markings, and finishes, but most importantly, by stone type. If you have been considering limestone for your new shower installation, you may be better off with quartzite. Keep reading to learn why.

About Limestone

Formed in shell beds and composed primarily of sedimentary calcite, limestone may contain small marine fossils. It is a beautiful stone, but it is also soft and prone to etching and staining. The success of a limestone shower installation depends on its density and porosity, which can be difficult to determine at the time of purchase. While some installations may be trouble-free, others can present difficulties.

Fred Hueston, Chief Technical Director for Stone and Tile PROS, warns, “People use limestone in showers all the time, but it can be very high maintenance, and sometimes it can be problematic, especially light colored stone. Iron oxidation rusting can be a major issue. I have seen all kinds of problems with limestone in showers, from spalling and flaking to discoloration due to moisture intrusion.”

Can you use quartzite in a shower?

A metamorphosed and slightly iridescent sandstone, quartzite is often used in outdoor areas, but is perfectly suitable for interior use, as well. According to Hueston, quartzite is a more reliable substitute for people who have been eyeing limestone for a shower installation. There are a few pro quos, however. He says, “I would recommend quartzite for a shower installation, assuming it is properly installed, and assuming it is pure quartzite, not marble being sold as quartzite, a common shady practice in the market today.”

Obviously, one should be careful to choose a reputable fabricator when having quartzite, or any stone for that matter, installed in a shower. Feel free to contact us with any specific questions you may have about selecting natural stone for your shower installation.

Sealing Stone in Wet Conditions

There are no pat answers to sealing natural stone, which is why we recommend that an informed professional always be called on for determining the best solutions for your stone. Not only are there are many types of sealers that perform differently and accomplish different things, as you will see in the following article from Fred M. Hueston, Chief Technical Director for Surface Care and troubleshooting expert, sometimes sealing may not be appropriate at all…

I receive several calls a week with questions about the use of impregnating-type sealers for use on outdoor stone as well as interior stone, such as showers, water fountains, and other wet areas. The questions are all basically the same: Should I seal my stone in wet conditions? Let me explain why stone in wet areas should not be sealed.

But first, there are a couple of definitions you’ll need to know…

Impregnators or penetrating sealers: Impregnators are designed to penetrate below the surface of the stone and deposit solid particles in the pores of the stone or to coat the individual minerals below the surface of the stone. These sealers restrict water, oil, and dirt from entering the stone. Impregnators can be solvent or water based. Most impregnators are vapor permeable.

Vapor permeable: Vapor permeability describes a stones breathability, or the ability to allow water vapor to pass through it.

The Case for Not Sealing Stone in Wet Environments

Most of the impregnators on the market today are breathable. This simple means that the stone will be protected from water entering the pores of the stone in liquid form but will allow water vapor to pass. Sometimes, stone is exposed to unregulated humidity and temperature fluctuations, and the result is condensation. Impregnators are breathable. Therefore, vapor can easily penetrate into the stone. One would think that this is positive, but once the vapor enters the stone it can condense and become a liquid. Since impregnators protect against water in its liquid phase, the moisture becomes trapped within the stones pores and will not escape until it turns into vapor and evaporates.

Trapped moisture can result in all kinds of problems. For example, stones with iron content can oxidize. If there are natural salts within the stone, the salt can dissolve and cause pitting and spalling in the surface of the stone. Aesthetically, the stone will appear darker since it is constantly wet.

More Research Will Be Necessary

There are currently several people in the natural stone industry doing experiments to demonstrate that sealer in wet environments can cause these issues and to discover in what circumstances, if any, sealers in wet environments may be appropriate. For example, sealed shower walls may be fine, while sealing the shower floor may pose problems. Although their findings are not yet published, I strongly believe that care should be taken when sealing stone in wet environments.

What is resined natural stone?

Resined natural stone is stone that is treated to improve minor naturally occurring flaws. Resining is achieved by drying unpolished slabs, spraying them with polyester, and placing the slabs in a vacuum chamber that sucks the resin deep into the stone. Once the stone has cured, it can be polished to any type of finish, from soft matte to a highly reflective polish.

What are the pros and cons of resining natural stone?

Natural stone has inherent imperfections, such as porosity, fissures, pitting, and the like. Resin fills, reinforces, and strengthens the durability of natural stone. According to Fred Hueston, Chief Technical Director for Stone and Tile PROS, some granites probably would not make it into the United States if it were not for the resining process, because the stone is so brittle, it would break during shipping. However, Hueston warns, “Resin strengthens the stone temporarily, but any time we introduce a man-made process into a natural material, things can go wrong. It might not be cured properly. It might not be dried properly. Polyester can become discolored when exposed to UV light.”

Resolving Resined Stone Problems

Fortunately, problems with resined stone can be resolved. For example, polyester resin can darken on the surface of a slab (which might not be noticeable, if it were not for polished edges revealing the true color of the stone). A trained, reputable natural stone restoration contractor can apply a high-quality color enhancer to achieve a uniform color, as well as repair and restore the like-new finish to unsightly stone.

Here’s a consumer question regarding their concern about a poultice leaving behind a bigger stain on marble.

A homeowner submitted the following question recently: “I had an oil stain on a marble surface and used a poultice of water and baking soda and left it on the stain for 24 hours. The result is that I now have a much darker stain which is now the size of where the paste was laid out. What would you suggest to remove what now appears to be a large water stain and etched surface? Blow dryer?”

The inquirer inaccurately named the problem a “stain,” but he understood correctly that what he was seeing was darkness from moisture that had wicked out beyond the original stained area, suggested by his question about using a blow dryer. This problem is normal and easy to resolve.

He also thought the marble had become etched from the poultice mixture. This so-called “etching” is another matter. Baking soda will not etch marble. It’s probable that what he was seeing was white residue left over from the baking soda. (If it were not, our first concern would be that he had scrubbed the baking soda and scratched the finish. If he had, then we would have needed to re-polish the area.)

Unsealed Stone Is Absorbent

Natural stone that is not sealed will not only allow a staining agent to penetrate, but it will absorb and stay wet for a while from the poultice application. This will cause the stone to appear darker. The effect can be likened to a pair of denim blue jeans. Any area on jeans that gets wet with water will appear darker than dry denim. It’s not a stain, and it will return to normal once it dries. Likewise, the darker stone technically is not stained, and will eventually dry out on its own, but there are ways to speed up the drying time.

Removing the Discoloration

We instructed our inquirer to spread cooking flour over the discoloration and allow it to dwell overnight. The flour would absorb the moisture, restoring the proper appearance to the stone underneath.

Does your stone need to be sealed?

There is a bigger issue here that needs to be addressed. If your natural stone needs to be sealed, it will absorb staining agents and moisture. In fact, a simple way to know if your stone is adequately sealed is to put a few drops of water on any areas that are used most often. Wait for a few minutes, then wipe the areas dry. If the surface of the stone does not darken, that means the stone is adequately sealed.

If your stone does need to be sealed, contact us to have it professionally cleaned and sealed.

Cloudy Countertops

Have you noticed a haze or cloudiness on the surface of your natural stone countertops? Natural stone countertops provide an elegant focal point for kitchens and bathrooms. But when the clarity of the finish is diminished by a haze or cloudiness, countertops quickly become an eyesore. There are a number of reasons why the problem develops. Here are the details about what causes this problem and what can be done to resolve it.

Improper Cleaning Products

People are often incorrectly advised to use window cleaner or soap water on countertops. Over time, a buildup of improper cleaning products can cause a haze or cloudiness to develop on the surface of the stone. Abrasive cleaners, such as scouring powder, can also damage the finish of a countertop. We always recommend pH-neutral, stone-safe cleaning products. If these products are not effective in removing the haze or cloudiness, it’s probably time to have your stone professionally cleaned and sealed or refinished.

Improper Cleaning Methods

Abrasive cleaning tools, just like abrasive cleaners, can destroy or damage the finish of natural stone countertops.

Oil-Based Spills

Oil-based spills that are not cleaned up right away can seep into the porous surface of the stone, causing the stone to develop a haze or cloudiness. Oil can be very difficult to remove on most stone. If it has dried on the surface, carefully use a sharp razor to scrape off the excess. Sprinkle a generous portion of poultice powder on the spill and let stand for 12-24 hours. Remove the dry poultice and prepare a solution of degreaser and water. Apply this solution to the spill and keep it wet for 30 minutes. Vacuum the solution up and blot the remainder with a clean white cloth. If the haze or cloudiness is still present, poultice with a solvent (commercial paint remover works well) and poultice powder.

Improper Sealer Application

Ideally, stone sealer is absorbed into the porous surface of the stone and does not affect the appearance of the finish at all. A haze or cloudiness can be caused by a stone sealer for a number of reasons. It may be because the wrong sealer is used. Sometimes a highly polished top doesn’t need to be sealed at all, therefore the sealer doesn’t absorb into the stone. Even if the stone does need to be sealed and the appropriate sealer is used, a haze or cloudiness can still develop if the sealer is improperly applied. A professional stone restoration contractor will need to resolve this situation.

Hard Water Deposits

Hard water deposits can cause a haze or cloudiness on the surface of natural stone. Sometimes, if the buildup is not too severe, it can be safely removed using pH-neutral, stone-safe cleaner. If not, a professional restoration contractor can restore the finish.

Feel free to contact us with questions or concerns about removing a haze or cloudiness from the surface of your natural stone countertops.

Kitchen countertops, bathroom vanity tops, bar tops, and the like are especially prone to staining because they are exposed to oily or dye-containing substances on a daily, or sometimes, even an hourly basis. Consequently, a sealer should be applied to inhibit staining. Choosing the correct type of sealer can be very important for how the sealer performs. An experienced, professional stone restoration contractor will know which sealer is best, taking into consideration the characteristics of the particular type of stone to which it will be applied and the location where the stone is used.

Impregnating Sealers

Impregnating sealers, also known as penetrating sealers, are the most commonly used sealers. Applied to natural stone to inhibit staining, impregnating sealers penetrate below the surface and protect the stone from within. They are formulated with water-repellent and oil-repellent substances. Topical sealers are available, but can be problematic, and in most cases, they are not recommended.

Misconceptions About Sealers

There are many misconceptions about what a sealer does and doesn’t do. It is important to note that sealers do not prevent traffic patterns or etching. The surface of the stone is still vulnerable to acidic substances, scratches, dullness, and other damage. In addition, natural stone, even when it is properly sealed, is not stain proof, it is merely stain resistant. In other words, it buys some time so that spills can be cleaned before they penetrate into the stone and become stains. After natural stone is sealed, it still needs to be regularly cleaned with pH neutral stone care products and periodically refinished.

New High Performance Protective Treatments

There are new protective treatments that, unlike impregnating sealers, offer both etch and stain protection.

Ask us about how we can protect your natural stone.