TNC Granite


What’s the difference between marble and granite?

Although both are stones and both are quarried from the earth, granite and marble (and marble’s relatives - limestone, onyx and travertine) are very different from each other. Granite is formed deep in the earth’s mantle at extremely high temperatures, and is a very hard, resistant stone made of crystallized minerals. The marble family - limestone, travertine, marble, onyx - starts out as sediment - animal skeletons and shells, plant matter, silt - at the bottom of bodies of water. After millions of years this solidifies (lithifies) into stone. Because its main component is calcium, it can be affected by acids such as vinegar and citrus beverages.

Why is granite good for kitchen counters?

Because granite is very hard stone that’s formed at very high temperatures deep in the earth, its polish is not subject to etching by household acids, or scratching by knives and pots and pans. It’s unaffected by typical kitchen heat such as hot pans, or spilled liquid.

What is travertine? Is travertine the same as limestone?

Travertine is limestone, in a sense. It is formed by geysers, like Old Faithful, when the extremely hot underground water dissolves the underlying limestone and carries it upwards with the geyser water. When the water falls to the ground and evaporates, it leaves behind the dissolved limestone which re-hardens into stone. Like PerrierTM waters, the new stone is full of gas bubbles, which give travertine its characteristic appearance. When it is manufactured as tiles or slabs, travertine is generally filled with cement and polished or honed.

Is it necessary to seal stone?

All stone, even granite, is porous to some degree, and will absorb stains over time. Some stones are more porous than others, so it is important to use a penetrating sealer to prevent stains from oil, wine, or other liquids from soaking into the surface.

My little sample of granite has pits on the surface - will I have these on my kitchen counters?

Granite, which is crystalline in structure, always has tiny pits - spaces between the various mineral crystals. You don’t see them on a larger piece because the overall appearance is polished and mirror-like. Granite sometimes has natural fissures as well, which may look like cracks, but are not structural defects and are a naturally occurring result of the immense heat and pressure which formed the granite eons ago. These characteristics are part of the natural beauty of stone and will not impair the function or durability of the material. A product of nature cannot be expected to look manmade.

Can I cut on my granite countertop?

Only if you want to ruin your good knives. Granite is harder than your knife blades and will dull them very quickly, if you use the countertop as a cutting surface. Always cut and chop on a wooden or plastic cutting board.

What is honed marble or limestone and where is can it be used?

Marble, travertine, or limestone that is honed has a matte or satin finish, rather than a high reflective polish. This is achieved at the factory by stopping just short of the last stage of polishing. Some fabricators have special equipment and can hone marble in their shops by removing the factory polish. One feature of honed marble is that it doesn’t show etching as readily, or wear patterns on floors. It is preferred by some because it has a less formal, softer appearance than polished stone.

What is etching?

Etching happens when acid in some form comes in contact with a polished marble or limestone surface. This causes a chemical reaction which removes the polish, or roughens the surface of honed marble or limestone. Green marbles, such as the “jades” from China are resistant to etching, and granite is impervious to any common household acids.

What’s the best way to clean marble and other stones?

The old rule of thumb is never to use anything you wouldn’t use on your hands. Never use powdered cleansers or abrasive pads to clean your stone. Even “soft scrub” type cleaners contain pumice, which is powdered volcanic stone, and might damage your stone countertops or floors. Never use any product which is acidic; this includes substances like ammonia or many common liquid cleaners such as WindexTM. You should always use sealers and cleaning products designed specifically for natural stone.

Can I use limestone in my kitchen?

Like marble, polished limestone is subject to surface changes or damage from kitchen acids including citrus juices, vinegars, mustards, and so forth. Unsealed, some of the more porous limestones can be subject to stains. If the limestone is polished or semipolished, you will see a rough spot where the substance sat on the stone. On a honed surface, such etches will be less noticeable.

Is limestone soft and chalky?

No, not at all. There are some limestones such as Beauharnais that are very hard and dense, nearly as hard and resistant as granite, and extremely non-porous. Keep in mind, though, that these very hard limestones are still calcium-based and, if polished, are subject to damage from household acids.

What does “crosscut” mean?

“Crosscut” refers to a particular way of slicing a block of stone. The traditional way of cutting layered material such as Travertine is the “vein cut,” similar to cutting with the grain of a piece of wood, so that the layers of material appear as parallel stripes or layers. If the block is cut across the grain, it yields a very different look, like cutting across the grain of a piece of wood.

To what does fleuri or fiorito refer?

Fleuri and fiorito are the French and Italian words for “flowered,” and refer to a way of slicing blocks of some kinds of stone. It is sometimes used to mean the same thing as “crosscut,” because of the “flowers” that appear as the end of veins. Technically, with bedded or layered material, a fleuri or fiorito cut is with the bed, per the diagram, and the “flowers” are the high and low spots of the beds.

What kind of stone can I use on my swimming pool deck and other wet areas?

There are a number of materials that can be used to provide a non-slip surface, including flamed granite tiles. For hot areas, the ideal deck surface is our Lumachela stone, which stays cool underfoot on the hottest of days. LS60UH, Terra Cotta, and LS80UH, Tuscany, provide a beautiful, natural and comfortable surface for your pool and patio.