Granite Countertops And Pitting…
We recently had a customer concerned about pitting in their countertops. While pitting is common in all granites, I wanted to explain the term a little more in depth.
Granite is one of the hardest materials available today for countertops. It is composed of a variety of different minerals, each having their own hardness. Granite is made of an assortment of minerals including quartz, feldspar, biotite, titanium oxides, as well as some other mineral combinations, depending on the color. According to “A Homeowner’s Guide to Natural Stone Countertop Installation,” a publication by the MIA, “On the Mohs Scale of Hardness, diamonds are the hardest mineral, with a rating of 10. Quartz and feldspar have a hardness of 6.5 to 7 and are very durable. Biotite (also known as mica) on the other hand is very soft (2.5) and flakes easily. All true granites have biotite in their composition, and because biotite is relatively soft and flaky, the first few layers are removed during the polishing process, causing pits throughout the slab.” Some granites contain more pitting than others, depending on the amount of biotite, or mica throughout the slab.
Although pits are common in all granites and occur naturally, it does not make the stone inferior. Over the years, pitting has become less noticeable for consumers because of the availability of resin-impregnated slabs. Many suppliers today, apply resin to their slabs in an effort to help fill pits, cracks, or fissures. “The procedure involves applying a resin over a sawn slab, usually in an automated process. The resin is allowed to cure, which may or may not be accelerated with a heat application. Once the resin is cured, the slab is then polished.” The polishing process removes most of the resin, leaving resin only in areas of pits, fissures, etc.
If you have questions pertaining to pitting when selecting granite for your countertops, please ask. We are glad to answer your questions.
Thanks for reading!
Barb
Posted in Granite, Industry News on April 8th, 2010 by Barb | | 2 Comments
on April 9th, 2010 at 1:28 am
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on April 9th, 2010 at 6:46 pm
Great post! I think you described it perfectly.
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