products / granites

Granites are plutonic rocks and one of the most common types of igneous rocks. In their structure, participate mineral elements such as quartz, alkali feldspars, and biotite. In the mineralogical composition of the granite, in some cases, participate in small amounts mineral such as magnesite, hematite, apatite, zircon, epidote, and tourmaline. The crystals of the minerals have, in general, the same size. Furthermore, the word granite come from the latin Granum (= grain) in reference to the coarse-grained structure of such a crystalline rock.

The vibrant colours of that rock, its great endurance and hardness, the exceptional brightness and polish after the polishing process, properties which keeps for a very long time due to the silicic elements which contains, the homogeneity of its colours, as well as the capability of colour combinations with other materials, among them marbles, are some of the advantages which attract the interest of the architects and designers. The last years, granite, a rock with a great colour and type variety, is being used more and more in decoration of external sites and in internal applications mainly in kitchen countertops, in bathrooms etc.

The Truth About Granite and Radon/Radiation

Radiation: It’s All Around Us

It’s in the air we breathe, in the water we drink, in the soil and rock we stand on, and in the sun’s rays we like to bask in! Added to this is the radiation we get from man-made sources, such as x-rays, medical treatments, building materials, etc.

Radiation in Granite is Not Dangerous

From what we know, there are two ways in which countertops, tiles and other finishes made of granite might emit any level of radiation. The first is by the release of tiny amounts of the radioactive gas radon which can be inhaled. The second is by direct radiation from the surface itself to the homeowner. In both cases, the radiation emitted is from the same process – natural radioactive decay of one element into another. Compared to other radiation sources in the home and outside, the risk to the homeowner from radioactivity emitted from a granite countertop or tiles is practically non-existent. In fact, the amount of radon gas emitted by a granite countertop is less than one millionth of that already present in the household air from other sources.

Typical Contributions to Radon Content of Indoor Air (pCi/L)

• 69.3% Soil around house
• 18.5% Well water
• 9.2% Outdoor air
• 2.5% Building materials
• 0.5% Public water supplies

Over the past few years there has been some consumer confusion about rumored radiation levels occurring in natural granites used for residential countertops, floors, tiles, etc. Unfortunately, the origins of these concerns are advertisements and other communications from the manufacturers of radon detection devices and the producers of competing materials. Levels of radiation from granite products, which technically are measurable, are in fact, small fractional values of established thresholds for environmental safety.

The truth of the matter is that granite is a safe product. It’s been used for thousands of years and the relationship between granite and radon has been studied for years and years. How safe is granite? There have been mathematical models developed that show that one could live in an all-granite home or building, including sleeping on granite, for an entire year and still be within very safe levels of exposure.

Calculations show that, for an average countertop, containing an average uranium concentration of four ppm (parts per million), the concentration of radon that is given off by the countertop into the household air is 270,000 times less than the level of radon in the outside air. The maximum contact level that you would receive over one year if you were to sit on a countertop all of the time would be about one quarter of the annual radiation from all sources. If you were just a few inches away from the granite (such as when doing the dishes), the dose would be too low to measure.

(Source: Marble Institute of America)

Granites