Is granite radioactive?!?

Question

b/c there is this crazy lady here saying that it is... is it?!

Answer 1

A popular myth about granite is its (possible) radioactivity. Let's take a closer look at this matter and find out about the radioactivity of granite and other natural stones.

To give you the short answer: Yes. As well as the chair you are sitting on, the air you are breathing every day and the soil you are standing on. Basically everything in nature has some level or radioactivity. However, the radioactivity of granite (or your chair) is not so high that it could produce any harm.

A more cientific explanation is that there is the so called External Exposure to radioactivity of every human being. The level of the External Exposure is about 0.7 mSv/a. It is composed by the radioactivity that hits the earth from space and from the sun (cosmis and solar radiation), and by the radioactivity of small quantities of radioactive elements almost anywhere around us.

The cosmic radiation is of aproximately 0.3 mSv/a, while the radioactivity of the environment is of about 0.4 mSv/a. For more detailed cientific information see for example this study by the GSF-National Research Center for Environment and Health at the Technische Universität München.

The radioactivity of all the materials around us comes from tiny quantities of mostly uranium that is inside of almost any natural material. Sedimentary rocks (like sandstone for example) contain about one to four micrograms of uranium per gram of rock. Igneous rocks (that is basalt or granite) can contain between 0.5 to four micrograms of uranium per gram of rock. Sounds quite a lot. However, usual sand (like beach sand for instance) contains about three micrograms of uranium per gram of sand. And the average soil contains one to three micrograms of uranium per gram.

The radioactivity of granite and marble is therefore not higher than the radioactivity of any other natural object around

Answer 2

NOPE... just a rock...

Answer 3

Some varieties of granite are very slightly radioactive depending where they are from. There is however no danger from using these types of granite as the quantities of radiation emitted are microscopic and hardly above the normal background radiation level. The worry came from an article relating to the production of Radon by uranium containing granite and was, as always, blown right out of proportion. I had a house in Cornwall in England which is a natural radiation "hot spot" It had a huge cellar cut into the solid granite on which it was built and as there were no windows in the cellar I did have to have a ventilation system fitted to make sure any Radon gas build up was fully cleared although there was no history of residents dropping dead at an early age during the 350 years the house had been occupied.

To worry about your counter tops is totally unnecessary and just another bit of  scare mongering by the uneducated who have nothing better to do.

Answer 4

i wouldn't think so because they use it in houses for counters and i don't thin any city would allow radioactive materials to be eaten off of