The many faces of stone include (left to right) lava flow that creates Igneous stone that has been solidified from molten rock; Sedimentary stone created from a blend of organic materials and eroded earth; and Metamorphic stone (seen here in a close up photo) that evolves when one type of stone changes in form over time, usually the result of extreme heat or pressure.


The tile and stone industry has moved past its one-size-fits-all approach to installation products. Whether it’s surface prep, thinsets or even grouts, the products nowadays are often tailored to specific conditions, environments, materials and applications. This, of course, is great news for tile contractors who now benefit from many new job-specific products to work with.

This new generation of installation products is evidence that makers of tile and stone installation products are paying close attention to the needs of professionals in the field. As technology has progressed, manufacturers have been able to develop products that address specific problems and contribute to the long-term success of projects.

The trend toward specialized products also coincides with a sharp increase in the demand for natural stone installations. It is not just overall volume that’s up. We are seeing stone in places where it was never used before and we are seeing a wider variety of natural stone materials.

Stone is in heavy demand for new home upgrades and remodels, and homeowners are choosing from a wider variety than ever when they decide what to put down in their kitchen and bath upgrades and patios. While granite is still the most popular, accounting for about 44 percent of all U.S. stone imports, travertine, marble, limestone and slate have also caught on. They are showing up in floors, countertops, walls, shower and tub surrounds, pool decks and outdoor hardscapes.

To be sure, there has been a surge in stone use, and that has led to a need for specialized care that is just now catching up to demand.

The many faces of stone include (left to right) lava flow that creates Igneous stone that has been solidified from molten rock; Sedimentary stone created from a blend of organic materials and eroded earth; and Metamorphic stone (seen here in a close up photo) that evolves when one type of stone changes in form over time, usually the result of extreme heat or pressure.

Understanding Stone Types

To ensure proper care for stone installations and preserve the natural beauty, it is important to understand how stone is created. Different types of stone have unique, complex mineral compositions that determine density, porosity, hardness and absorption rates. Stone is categorized in two ways – by its mineral composition, and by its geological formation. Both affect its properties. Stone used for commercial purposes is either siliceous stone, or calcareous stone. Siliceous means it is made of silica, Earth’s most common mineral. It is very hard, highly durable, and easy to maintain. The second most common mineral group, calcareous stone, is softer and more porous. While it too is durable, it is sensitive to acids-including those found in common household cleaners.

There are three categories of geological stone formations: Igneous, Sedimentary and Metamorphic. Each of these stone-types is formed by a distinct process that occurs over millions of years. For those in the stone business, it is important to know something about each one:
  • Igneous stone is solidified molten rock that has been formed under pressure. Called magma when it is underground and lava when it is above the Earth’s surface, this molten rock cools and forms different varieties of igneous rock. Granite is the most commonly used igneous stone. It is a coarse-grained, siliceous-based stone with an even, crystallized texture.

    A very hard stone, granite is prized for its high density, low porosity and ease of maintenance. Still, granite does have microscopic cracks and fissures between its crystals that make it susceptible to oil- and water-based stains, so proper sealing and cleaning is important.
  • Sedimentary stone is created from a blend of minerals, organic plant and skeletal materials that have been broken down by glaciers, wind, rivers and oceans to form rock beds. Two of the most common types are limestone and travertine. Limestone is derived from seawater and contains minerals and ancient sea life. Its texture varies from medium to fine, and generally does not exhibit much graining or crystalline structure. Limestone varies in hardness and is highly porous, making it more susceptible to staining than most other commonly-used stone. Travertine is a variety of limestone and marble that contains holes formed by pressure, heat and water. These holes are usually filled with resin or other fillers during the fabrication process to create a flat, polished surface, but sometimes travertine is “tumbled” instead to give it a slightly rough old-world appearance.
  • Metamorphic stone is created, just as the name implies, from a metamorphism process during which a type of rock formation changes form over time, usually as a result of extreme heat or pressure. The original rock formations may be igneous, sedimentary or another, older metamorphic stone. Typical metamorphic stones are slate, a fine-grained stone formed when sedimentary rock such as shale is changed under high pressure, and marble. Marble was once limestone, compacted by pressure and heat and re-crystallized. They are beautiful but delicate stones. They are prone to staining and require significant care to maintain their appearance.


The many faces of stone include (left to right) lava flow that creates Igneous stone that has been solidified from molten rock; Sedimentary stone created from a blend of organic materials and eroded earth; and Metamorphic stone (seen here in a close up photo) that evolves when one type of stone changes in form over time, usually the result of extreme heat or pressure.

Finishes Make a Difference

The type of finish used during a stone’s fabrication process has a significant effect not only on its final appearance, but its porosity as well. Three of the most popular finishes-polished, tumbled and honed-each have their own specific qualities and, under powerful magnification, it’s easy to see the differences in stone types and finishes:
  • Polished stone has a very glossy, reflective surface. Its smooth finish brings out the grains and brilliant colors in the stone’s crystals, and also reduces porosity. The shine is the result of the natural reflection of the stone’s crystals, and can wear away if subjected to heavy foot traffic and improper maintenance.
  • A tumbled finish has a slightly rough texture, and is achieved by tumbling the stone with small bits of limestone, marble or granite to yield a worn, old-world appearance. Because the tumbling process does not have the same sealing effect as polishing, tumbled stone is more porous and more susceptible to staining than its polished counterparts.
  • Honed stone is highly porous and suitable only for low-traffic areas where the aesthetics are a chief consideration.

    Stone with a flat matte or low sheen gloss has a honed finish. Its surface is very smooth, but without the high gloss and vibrant colors characteristic of a polished finish.



A bathroom sink crafted from limestone, one example of the many new ways stone is being used as an innovative design tool.

Proper Care Maintains Both Beauty and Reputations

A close look at the significant differences in these types of natural stone and stone finishes indicate why each requires special care for optimal results. Remember, each stone reacts differently to the chemical formulas of sealers and cleaners.

Water-based sealers are easy-to-use, non-flammable and contain no toxic fumes. Although solvent-based sealers are equally effective in some formulations, they have a down side: They can be costly, flammable and hazardous to handle, requiring special breathing apparatus and safety equipment during their application. The water and solvents used in sealers are merely the carriers, delivering the active materials that protect the stone.

General purpose sealers contain various sealing molecules that will penetrate and bond, but some won’t and will simply be washed away. An ideal sealer is formulated with the right amounts of molecules to chemically bond with specific stone types and finishes, providing maximum protection.

Common household cleaners should never be used on stone as they often contain acids or harsh solvents that can erode the stone or even etch its finish – ruining the stone completely. The acids can also create larger pores in the stone which increases the potential for staining.

Today more and more tile contractors and consumers are realizing that they cannot use a one-size-fits-all approach to stone care. Scientific research and manufacturing know-how are putting optimized solutions in their hands. Today there are granite cleaners and polishers designed to permeate a dense surface and seal microscopic pockets to protect against stains. We now have sealers and acid-free cleaners that seal the larger voids in tumbled marble and clean without etching and scratching. These specialized solutions protect more than the consumer’s investment. They also protect the reputation of contractors by ensuring the long-term beauty of natural stone installations they lay down.