Setting Expectations for Natural Stone

Here are several factors to keep in mind:

1. All natural stone has inherent characteristics; it is natural; and therefore always imperfect. (Or perfectly imperfect, depending upon your view.)
2. Some materials are easier to maintain than others.
3. The appearance of natural stone will always patina over time. Without exception.
4. All natural stone should be set properly, sealed and maintained. This requires a well-researched setting, sealing and maintenance specification in order to avoid surprises.

Below are some general guidelines:

BASALT Basalt is a porous material with naturally occurring holes that may remain unfilled or be factory-filled with resin or cement. Basalt will stain when exposed to oil and highly-pigmented liquids.

HELPFUL TIPS:

• Do not use resin-filled material outside, as the resin will discolor over time. Choose cement-filled or unfilled materials as an alternative.
• Always seal this material prior to grouting or use.
• Always use a grout that is similar in color to the stone to avoid a picture-frame effect.
• To reduce the appearance of staining in kitchen countertop applications, always wipe up spills immediately. Oil and highly-pigmented liquids can penetrate and stain the stone and may need poultice to remove the stain.

GRANITE Some granites have higher absorption and/or lower abrasion resistance than may be expected. Some granites are resin-treated to enhance the color and fortify the surface of the stone.

HELPFUL TIPS:

• Always check the absorption rating.
• Always check the abrasion resistance rating.
• Always seal this material prior to use.
• Do not use resin-filled material outside, as the resin will discolor over time.
• Fabricators will often need to resin-treat the exposed edges to match the surface of the material.

LIMESTONE All limestones will acid etch when exposed to acidic foods such as lemons or tomatoes. Most limestones have high absorption ratings and low abrasion resistance ratings. In general, light-colored limestone is difficult to maintain in flooring applications with heavier traffic, gray limestone tends to effloresce in wet areas, and black limestone tends to show more scratching.

HELPFUL TIPS:

• Do not use limestone for kitchen countertop applications.
• Always seal limestone prior to grouting or use.
• Always check the absorption rating.
• Always check the abrasion resistance rating. For limestone with a lower abrasion resistance rating, use walk-off mats at entrances and expect the material to patina rapidly.
• Always use a grout that is similar in color to the stone to avoid a picture-frame effect.
• Always use a PH neutral detergent to clean limestone.
• If maintenance is an issue, choose a limestone with a lower absorption rating and higher abrasion resistance.
• To reduce the appearance of staining, always wipe up spills immediately. Oil and highly-pigmented liquids can penetrate and stain the stone and may need poultice to remove the stain.

MARBLE All marble will acid etch when exposed to acidic foods such as lemons or tomatoes. Most marble has a moderate absorption rating and will stain when exposed to oil and highly-pigmented liquids. Many variations have low abrasion resistance ratings and are likely to scratch. It is also common for marble to have naturally occurring cracks and fissures. In general, light-colored marble is difficult to maintain in flooring applications with heavier traffic and dark marble tends to show more scratching.

HELPFUL TIPS:

• Always seal marble prior to use.
• To reduce the appearance of etching in kitchen countertop applications, choose a honed, white marble with a low-moderate absorption rating.
• To reduce the appearance of staining, always wipe up spills immediately. Oil and highly-pigmented liquids can penetrate and stain the stone and may need poultice to remove the stain.
• Always use a PH neutral detergent to clean marble.
• Always check the abrasion resistance rating. For marble with a lower abrasion resistance rating, use walk-off mats at entrances and expect the material to patina rapidly.
• If acid etching is an issue, choose a material with minimal acid sensitivity rating, such as quartzite or granite.
• Expect to see factory-repaired cracks and fissures. The quality of the repair is dependent upon the factory of origin, the fabricator of the stone and the installer.

ONYX All onyx will acid etch when exposed to acidic foods such as lemons or tomatoes. Most onyx has a moderate absorption rating and will stain when exposed to oil and highly-pigmented liquids. All onyx has a very low abrasion resistance rating; it will scratch, stun and crack. All onyx has naturally occurring cracks and fissures.

HELPFUL TIPS:

• Onyx must be handled with extreme care in both fabrication and installation.
• Onyx is suitable for interior wall applications, not for floors. Onyx is sometimes used on vanities and other non-food service countertops; in these instances, the end user must be made aware of its acid sensitivity and fragility.
• Always use a PH neutral detergent to clean onyx.
• Expect to see factory-repaired cracks and fissures. The quality of the repair is dependent upon the factory of origin, the fabricator of the stone and the installer.

QUARTZITE Due to the incredibly high abrasion resistance of quartzite it can be difficult to quarry and fabricate. This affects availability, fabrication lead times and cost. Some quartzites have high absorption ratings and will stain when exposed to oil and highly-pigmented liquids. Most quartzite has naturally occurring cracks and fissures.

HELPFUL TIPS:

• Always seal quartzite prior to use.
• Always check the absorption rating.
• Expect to see factory-repaired cracks and fissures. The quality of the repair is dependent upon the factory of origin, the fabricator of the stone and the installer.

SANDSTONE All sandstones have high absorption ratings and medium abrasion resistance ratings; it will stain when exposed to oil and highly-pigmented liquids. Due to its absorbency and mineral make-up, sandstone has a tendency to warp during installation.

HELPFUL TIPS:

• Always seal sandstone prior to grouting or use.
• Always check the absorption rating.
• Always use a grout that is similar in color to the stone to avoid a picture-frame effect.
• To reduce the appearance of staining, always wipe up spills immediately. Oil and highly-pigmented liquids can penetrate and stain the stone and may need poultice to remove the stain.
• To prevent warpage, use a rapid setting adhesive.

SCHIST All schists have a moderate absorption rating and will stain when exposed to oil and highly-pigmented liquids. All schists have a low abrasion resistance rating and are likely to scratch.

HELPFUL TIPS:

• Always seal schist prior to grouting or use.
• Always use a grout that is similar in color to the stone to avoid a picture-frame effect.
• To reduce the appearance of staining, always wipe up spills immediately. Oil and highly-pigmented liquids can penetrate and stain the stone and may need poultice to remove the stain.
• Use walk-off mats at entrances and expect the material to patina rapidly.

SLATE All slates have a moderate absorption rating and will stain when exposed to oil and highly-pigmented liquids. All slates have a low abrasion resistance rating and are likely to scratch.

HELPFUL TIPS:

• Always seal slate prior to grouting or use.
• To reduce the appearance of staining, always wipe up spills immediately. Oil and highly-pigmented liquids can penetrate and stain the stone and may need poultice to remove the stain.
• Use walk-off mats at entrances and expect the material to patina rapidly.

TRAVERTINE Travertine is a porous material with naturally-occurring holes that may remain unfilled or be factory-filled with resin or cement. All travertines will acid etch when exposed to acidic foods such as lemons or tomatoes. All travertines have high absorption ratings and low abrasion resistance ratings.

HELPFUL TIPS:

• Do not use resin-filled material outside, as the resin will discolor over time. Choose cement-filled or unfilled materials as an alternative.
• Fabricators will often need to resin-fill the exposed edges to match the filled surface of the material.
• Do not use travertine for kitchen countertop applications.
• Always seal travertine prior to grouting or use.
• Use walk-off mats at entrances and expect the material to patina rapidly.
• Always use a grout that is similar in color to the stone to avoid a picture-frame effect.
• Always use a PH neutral detergent to clean travertine.
• To reduce the appearance of staining, always wipe up spills immediately. Oil and highly-pigmented liquids can penetrate and stain the stone and may need poultice to remove the stain.