Preserving the Beauty of your Natural Stone
The natural stone you have purchased for your home or office is an investment that will give you many years of beautiful service. Simple care and maintenance will help preserve your stone’s beauty for generations to come.
This page has been taken from a brochure that has been developed for you by the Marble Institute of America (MIA) to offer routine cleaning guidelines as well as procedures for stain removal should it become necessary.
Care and Precautions
Use coasters under all glasses, particularly those containing alcohol or citrus juices. Many common foods and drinks contain acids that will etch or dull the surface of many stones. Do not place hot items directly on the stone surface. Use trivets or mats under hot dishes and place mats under china, ceramics, silver or other objects that can scratch the surface.
Cleaning Procedures and Recommendations
Clean stone surfaces with a few drops of neutral cleaner, stone soap or a mild liquid dish washing detergent and warm water. Use a clean rag, a soft cloth or a microfiber cloth for best results. Too much cleaner or soap may leave a film and cause streaks. Do not use products that contain lemon, vinegar, or other acids on marble or other calcareous stones. Rinse the surface thoroughly after washing with soap solution and dry with a soft cloth. Change the rinse water frequently. Do not use scouring powders or creams; these products contain abrasives that may scratch the stone.
Vanity tops may need to have a penetrating sealer applied. Check with us for recommendations. A good quality marble wax or non-yellowing automobile paste wax can be applied to minimize water spotting.
In food preparation areas, the stone may need to have a penetrating sealer applied. Check with us for recommendations. If a sealer is applied, make sure that it is non-toxic and safe for use on food preparation surfaces.
Know Your Stone
Natural stone can be classified into two general categories according to its composition: siliceous stone or calcareous stone. Knowing the difference is critical when selecting cleaning products.
Siliceous stone is composed mainly of silica or quartz – like particles. It tends to be very durable and relatively easy to clean with mild acidic cleaning solutions. Types of siliceous stone include granite, slate, sandstone, and quartzite.
Calcareous stone is composed mainly of calcium carbonate. It is sensitive to acidic cleaning products and frequently requires different cleaning procedures than siliceous stone. Types of calcareous stone include marble, travertine, limestone and onyx. What may work on siliceous stone may not be suitable on calcareous surfaces.
How to tell the difference
A simple acid sensitivity test can be performed to determine whether a stone is calcareous or siliceous. You will need about 4 oz. of a 10% solution of muriatic acid and an eye dropper or you can use household vinegar and an eye dropper. Because this test may permanently etch the stone, select an out of the way area and be sure that you’re testing several inches away from the mortar joint. Apply a few drops of the acid solution to the stone surface on an area about the size of a quarter. If the stone is calcareous, the acid drops will begin to bubble or fizz vigorously. If little or no reaction occurs, the stone can be considered siliceous. Rinse the area thoroughly with clean water and wipe dry. This test may not be effective if surface sealers or liquid polishes have been applied. If an old sealer is present, chip a small piece of stone away and apply the acid solution to the fractured surface. CAUTION: Muriatic acid is corrosive and is considered to be a hazardous substance. Proper head and body protection is necessary when acid is used.
A polished finish on the stone has a glossy surface that reflects light and emphasizes the color and marking of the material. This type of finish is used on walls, furniture tops and other items, as well as floors.
A honed finish is a satin smooth surface with relatively little light reflection. Generally, a honed finish is preferred for floors, stair treads, thresholds and other locations where heavy traffic will wear off the polished finish. A honed finish may also be used on furniture tops and other surfaces.
A flamed finish is a rough textured surface used frequently on granite floor tiles.
Stone Colors and Appearance
Granites and marbles are quarried throughout the world in a variety of colors with varying mineral compositions. In most cases, marbles and granites can be identified by visible particles at the surface of the stone. Marble will normally show “veins” or high concentrations. The minerals in granite will typically appear as small flecks distributed uniformly in the stone. Each type of stone is unique and will vary in color, texture and marking.
Sandstones vary widely in color due to different minerals and clays found in the stone. Sandstone is light gray to yellow or red. A dark reddish brown sandstone, also called brownstone, has commonly been used in the northeastern United States and eastern Canada. Bluestone is a dense, hard, fine – grained sandstone of greenish – gray or bluish – gray and is quarried in the eastern United States.
Limestone is a widely used building stone with colors typically light gray, tan, or buff. A distinguishing characteristic of many limestones is the presence of fossils that are frequently visible in the stone surface.
Slate is dark green, black, gray, dark red or multi – colored. It is most commonly used as a flooring material and for roof tiles and is often distinguished by its distinct cleft texture.
Spills and Stains
Blot the spill with a paper towel immediately. Don’t wipe the area, it will spread the spill. Flush the area with clean water and mild soap and rinse several times. Dry the area thoroughly with soft cloth. Repeat as necessary. If the stain remains, refer to the section of this page on Stain Remover.
Identifying the type of stain on the stone surface is the key to removing it. If you don’t know what caused the stain, play detective. Where is the stain located? Is it near a plant, a food service area, an area where cosmetics are used? What colors is it? What is the shape or pattern? What goes on in the area around the stain?
Surface stains can often be removed by cleaning with an appropriate cleaning product or household chemical. Deep – seated or stubborn stains may require using a poultice or calling a professional. The following selections describe the types of stains that you may have to deal with and appropriate household chemicals to use and how to prepare and apply a poultice to remove the stain.
Types of Stains and First Step Cleaning Actions
Oil – based (grease, tar, cooking oil, milk, cosmetics) An oil – based stain will darken the stone and normally must be chemically dissolved so the source of the stain can be flushed or rinsed away. Clean gently with a soft, liquid cleanser with bleach OR mineral spirits OR acetone.
Organic (coffee, tea, fruit, tobacco, paper, food, urine, leaves, bark, and bird droppings) may cause a pinkish – brown stain and may disappear after the source of the stain has been removed, normally the sun and rain action will generally bleach out the stains. Indoors, clean with 12% hydrogen peroxide (hair bleaching strength) and a few drops of ammonia.
Metal (iron, rust, copper, bronze). Iron or rust stains are orange to brown in color and follow the shape of the staining object such as nails, bolts, screws, cans, flower pots, metal furniture. Copper and bronze stains appear as green or muddy – brown and result from the action of moisture on nearby or embedded bronze, copper, or brass items. Metal stains must be removed with a poultice. (See section on Marking & Using a Poultice) Deep seated, rusty stains are extremely difficult to remove and the stone may be permanently stained.
Biological (algae, mildew, lichens, moss, fungi) clean with dilute (1/2 cup in a gallon of water) ammonia OR hydrogen peroxide. DO NOT MIX BLEACH AND AMMONIA! THIS COMBINATION CREATES A TOXIC AND LETHAL GAS!
Ink (magic marker, pen, and ink) clean with bleach or hydrogen peroxide (light colored stone only!) or lacquer thinner or acetone (dark stones only!)
Small paint amounts can be removed with lacquer thinner or scraped off carefully with a razor blade. Heavy paint coverage should be removed only with a commercial “heavy liquid” paint stripper available from hardware stores and paint centers. These stripers normally contain caustic soda or lye. Do not use acids or flame tools to strip paint from stone. Paint stripers can etch the surface of the stone: repolishing may be necessary. Follow the manufacturer’s directions for use of these products, taking care to flush the area thoroughly with clean water. Protect yourself with rubber gloves and eye protection, and work in a well ventilated area. Use only wood or plastic scrapers for removing the sludge and curdled paint. Normally, latex and acrylic paints will not cause staining. Oil – based paints, linseed oil, putty, caulks, and sealants may cause oily stains. Refer to the selection on oil – based stains.
Water Spots and Rings (surface accumulation of hard water) buff with very dry 0000 steal wool.
Fire and Smoke Damage – Older stones and smoke or fire stained fireplaces may require a through cleaning to restore their original appearance. Commercially available “smoke removers” may save time and effort.
Etch Marks are caused by acids left on the surface of the stone. Some material will etch the finish but not leave a stain. Others will both etch and stain. Once the stain has been removed, wet the surface with clean water and sprinkle on marble polishing powder, available from a hardware store, lapidary store, or your local stone dealer. Rub the powder into the stone with a damp cloth or by using a buffing pad with a low – speed power drill. Continue buffing until the etch mark disappears and the marble surface shines. Contact Universal Stone for refinishing or repolishing etch areas that you cannot remove.
Efflorescence is a white powder that may appear on the surface of the stone. It is caused by water carrying mineral salts from below the surface of the stone rising through the stone and evaporating. When the water evaporates, it leaves the powdery substance. If the installation is new, dust mop or vacuum the powder. You may have to do this several times as the stone dries out. Do not use water to remove the powder; it will only temporarily disappear. If the problem persists, contact Universal Stone to help identify and remove the cause of moisture.
Scratches and Nicks – Slight surface scratches may be buffed with dry 0000 steel wool. Deeper scratches and nicks in the surface of the stone should be repaired and repolished by a professional.
Do’s and Don’ts
CALL DEBEER GRANITE & MARBLE INC. FOR PROBLEMS THAT APPEAR TOO DIFFICULT TO TREAT.