The first step in proper stone care and maintenance is to understand your stone's
geological classification and composition. this
information will help you to identify what cleaning products to use and how best to care
for your natural stone.
Natural stone is categorized into three basic
geological classifications by their respective
formation processes: Sedimentary,
Metamorphic and igneous. Additionally, stones in each category can be either Calcareous or
Siliceous.
Calcareous stone is composed mainly of
calcium carbonate, a chemical compound
commonly found in natural stone, shells and
pearls. Calcium Carbonate is sensitive to acidic
solutions so mild, non-acidic cleaners are
recommended.
Siliceous stone, as the term implies, is one
composed primarily of silicates, such as quartz, feldspar, mica, etc. as such, a siliceous stone is generally resistant to most acids found in
kitchen settings, although acidic cleaners are
still not recommended, as these stones may contain trace levels of minerals that are acid
sensitive.
The following chart will be a helpful guide:
To get the longest life and preserve the beauty
of your natural stone, follow these simple tips:
Coasters: Use coasters under all glasses,
particularly those containing alcohol or citrus
juices.
Trivets: While many stones can withstand heat,
the use of trivets or mats is recommended. Dust Mopping: Dust mop interior floors
frequently using a clean non-treated dry dust mop. Sand, dirt and grit are abrasive and can
damage natural stone.
Mats/rugs: Mats or area rugs inside and outside
an entrance will help to minimize the sand, dirt
and grit that may scratch the stone floor. Be sure
that the underside of the mat or rug is a slip
resistant surface.
Vacuum cleaners: If used, be sure the metal or
plastic attachments or the wheels are not worn
as they can scratch the surface of some stones.
Spills: Blot the spill with a paper towel
immediately. Don't wipe the area, it will spread
the spill. Flush the area with water and mild
soap and rinse several times. Dry the area
thoroughly with a soft cloth. Repeat as
necessary.
Sealing is a common step taken on some stones
as an extra precaution against staining. In fact,
the sealing products used in the stone industry
are impregnators which do not actually seal the
stone, but more correctly act as a repellent
rather than a sealer. Sealing does not make the
stone stain proof, rather it makes the stone more
stain resistant. When consulting with your stone supplier, you may find that many stones do not
require sealing. However, applying an
impregnating sealer is a common practice.
When considering sealing, remember that
sealing the stone does not make the stone stain proof, it makes it more resistant to staining.
If a sealer is applied in a food preparation area, be sure that it is non-toxic and safe for use.
Consult with your supplier or sealing
manufacturer specific to the type of sealer and
frequency of use recommended.
Identifying the type of stain on the stone surface
is the key to removing it. Stains can be oil
based, organic, metallic, biological, ink based,
paint based, acid based. If you don't know what
caused the stain, consider likely staining agents
that may have been present. Here are some
questions you consider:
Surface stains can often be removed by cleaning with an appropriate cleaning product or household chemical.
The following sections describe the types of stains you may have to deal with and the appropriate household chemicals to use and how to prepare and apply a poultice to remove the stain.
(grease, plumbers' putty, 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 one of the following: household detergent,
mineral spirits, or acetone.
(coffee, tea, wine, 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,
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.
(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.
(algae, mildew, lichens, moss, fungi)
Clean with diluted cleaning solution. Use a 1/2 cup of any of the following: ammonia, bleach,
or hydrogen peroxide and a gallon of water.
Reminder: do not mix bleach and ammonia.
(magic marker, pen, ink)
On light colored stones, clean with bleach or hydrogen peroxide. On dark colored stones, clean with lacquer thinner or acetone.
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 paint 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; re-polishing may be necessary. Follow the manufacturer's directions for use of these products, and 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 section on oil-based stains.
(surface accumulation of hard water)
Buff with dry 0000 steel wool.
Older stones and smoke or fire-stained fireplaces may require a thorough cleaning. When the smoke is removed, there may also be some etching (due to carbonic & other acids in smoke). Commercially available "smoke removers" may save time and effort.
(caused by acids left on the surface of the stone)
Some materials will etch the finish but not leave a stain. Others will both etch and stain. Contact your stone dealer or call a professional stone restorer for refinishing or re-polishing etched areas.
(a white powder that may appear on the surface of the stone)
It is caused by the deposition of mineral salts carried by water from below the surface of the stone. 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 your installer to help identify and remove the cause of the moisture.
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 re-polished by a professional.
Using a Poultice
Call a stone professional (recommended).
Natural Stone Easy to Clean and Maintain!
Call your professional stone supplier, installer or a restoration specialist for problems that appear too difficult to handle.
Disclaimer
This document is written as a general guideline.
Corsi & Nicolai (Australia) Pty Ltd has neither liability nor can
they be responsible to any person or entity for any
misunderstanding, misuses, or misapplication that would cause
loss or damage of any kind, including loss of rights, material, or personal injury, or alleged to be caused directly or indirectly by the information contained in this document.
