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 information has been compiled 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.

For additional information on selecting and caring for natural stone, visit MIA's Website at www.usenaturalstone.com.

Care and Precautions
Use coasters under all glassees, 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 placemats under china, ceramics, silver or other objects that can scratch the surface.

Cleaning Procedures and Recommendations

Dust mop interior floors frequently using a clean non-treated dry dust op. Sand, dirt and grit do the most damage to natural stone surfaces to their abrasiveness. Mats or area rugs inside and outside an entrance will help to minimize the elements that can scratch the stone. Be sure that the underside of the mat or rug is a non-slip surface. Normally, it will take a person about eight steps on a floor surface to remove sand or dirt from the bottom of their shoes.

Do not use vacuum cleaners that are worn. The metal or plastic attachments of the wheels may scratch the surface.

Clean stone surfaces with a few drops of neutral cleaner, stone soap or a mild liquid dishwashing detergent and warm water. Use a clean rag mop on floors and a soft cloth for other surfaces 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 suface thoroughly after washing with the 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.

In the bath or other wet areas, soap scum can be minimized by using a squeegee after each use. to remove soap scum, use a non-acidic soap scum remover or a solution of ammonia and water (about 1/2 cup ammonia to a gallon of water). Frequent or over-use of an ammonia solution may eventually dull the surface of the stone.

Vanity tops may need to have a penetrating sealer applied. Check with your installer 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 your installer for recommendations. If a sealer is applied, be sure that it is non-toxic and safe for use on food preparation surfaces. If there is a question, check with the sealer manufacturer.

In outdoor pool, patio or hot tub areas flush with clear water and use mild bleach solution to remove algae or moss.

Know your stone

Natural stone can be classified into two general categories according to its composition: 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, quartzite, brownstone and bluestone.

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 silicious 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 eyedropper. 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 (a corner or closet) and 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 the 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.

Stone Finishes

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 floor tiles.

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, aalso 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 color and is quarried in the eastern United States.

Limstone 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 plain water and mild soap and rinse several times. Dry the area thoroughly with a soft cloth. Repeat as necessary. If the stain remains, refer to the section in this brochure on stain removal.

Stain Removal

Identifying the type of stain o 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 for service area, an area where cosmetics are used? What color 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 in a professional. The following sections 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 or bleach OR household detergent OR ammonia OR mineral spirits OR acetone.

ORGANIC
(coffee, tea, fruit, tobacco, paper, food, urine, leaves, bark, bird droppings)
May cause a pinkish-brown stain and may disappear after the source of the stain has been removed. Outdoors, with the sources removed, normal sun and rain actions 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. Deep-seated, rusty stains are extremely difficult to remove and the stone may be permanently stained.

BIOLOGICAL
(algae, mildew, lichens, moss, fungi)
Clean with dilution (1/2 cup in a gallon of water) ammonia OR bleach OR hydrogen peroxide. DO NOT MIX BLEACH AND AMMONIA! THIS COMBINATION CREATES A TOXIC AND LETHAL GAS!

INK
(magic marker, pen, ink)
Clean with bleach or hydrogen peroxide (light colored stone only!) or lacquer thinner or acetone (dark stones only)

PAINT
Small 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” pain stripper available from hardware stores and paint centers. These strippers normally contain caustic soda or lye. Do not use acids or flame tools to strip paint from stone. Paint strippers 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 staininig. Oil-based paints, linseed oil, putty, caulks and sealants may cause oily stains. Refer to the section on oil-based stains.

WATER SPOTS AND RINGS
(surface accumulation of hard water)
Buff with dry 0000 steel wool.

FIRE AND SMOKE DAMAGE
Older stones and smoke or firestained fireplaces may require a thorough cleaning to restore their original appearance. Commercially available “smoke removers” may save time and effort.

Dos and Don’ts

DO Dust mop floors frequently

DO Clean surfaces with mild detergent or stone soap

DO Thoroughly rinse and dry the surface after washing

DO Blot up spills immediately

DO Protect flor surfaces with non-slip mats or area rugs and countertop surfaces with coasters, trivets or placemats

DON'T Use vinegar, lemon juice or other cleaners containing acids on marble, limestone, travertine or onyx surfaces

DON'T Use cleaners that contain acid such as bathroom cleaners, grout cleaners or tub and tile cleaners

DON'T Use abrasive cleaners such as dry cleansers or soft cleansers

DON'T Mix bleach and ammonia; this combination creates a toxic and lethal gas

DON'T Ever mix chemicals together unless directions specifically instruct you to do so

Call your professional stone supplier, installer or a restoration specialist for problems that appear to difficult to treat.