When working with customers I will sometimes hear rather interesting questions. There is one that tends pop up every once in a while: “Is granite radioactive?” I always find granite radiation to be fun to talk about.
Granite is cooked in the earth for a very long time with a lot of heat and pressure. This slow process is what enables large mineral crystals to grow. These large crystals are what make the color and veins that people love about granite. Any stone cooked like this has the possibility of containing naturally radioactive materials like thorium, radium, and uranium. This means that all natural stones and even soil have a chance to be radioactive.
This is no reason to worry though. The amount of radiation that a stone countertop would put off is so low that it could never cause any kind of harm. One of the best pieces of evidence that support this is this study. People who work in quarries are cutting and breaking stone all day and as you can imagine are absolutely covered in stone dust and dirt. The study that I linked to tested these workers and found they were not being exposed to any meaningful levels of radiation. This means that even if you slept on a granite slab and sprinkled granite dust into your cereal every morning you would never be at any risk.
To put this granite radiation in perspective, bananas and Brazil nuts actually have a measurable amount of radiation output. However, you could swim in a pool of banana pudding everyday and hoard Brazil nuts like a squirrel without ever being at any risk.