Obviously, we all know that granite is a radioactive stone. That is why New Hampshirites glow in the dark, just kidding. But many older NH homes do have radon detectors in the basements. Now take that to the kitchen and imagine what is off-gasing from your countertops?
The level of radioactivity varies from stone to stone but one granite was tested and well, you can read for yourself -
"We measured more than 500 microR/hour of gamma radiation from a slab of Jupurana Bordeaux on display in the showroom. At that dose, a person in close contact with the granite for an hour a day would receive 182 millirem of gamma radiation in a year. The Nuclear Regulatory Commission (NRC) recommends that members of the public should not exceed 100 millirem/year above background. No more than 25 millirem/year should come from a single source, like granite counter tops."
I am not a scientist or a doctor but you have to wonder with the increased developmental problems they are seeing in children these days, autism, where is this coming from?
So especially if you have kids - think twice about granite, especially since there are so many, much more beautiful, environmentally responsible and healthier alternatives for your kitchen surface.