The easiest way to find out is to hire someone with a geiger counter to measure the levels coming off the granite. The truth is, most granite will emit a tiny amount of radioactive energy. What is coming off the granite counters is called radon progeny or radon daughters, and is the result of naturally occurring radioactive elements such as uranium or radium decaying. It can also emanate from basements, or any place the earth is exposed. In an outdoor setting it's harmless, as the radon becomes diluted with fresh air. But in confined settings such as basements or kitchens, it can build up, posing more of a health risk.

If your counter is emitting just a tiny amount, this isn't something to worry about. But some counters tested have hot-spots that emit levels of radiation that, with continued exposure, could cause health problems later on in life. And while some reports state that these dangers are more common in exotic colors like reds and purples, they've also been detected in the mottled beige to yellow counters that are actually quite common.

As gorgeous as granite is, it might be a good idea to have yours tested. The Environmental Protection Agency states that about 20,000 people die annually from lung cancer related to radon exposure. That's not something to ignore. If your levels are low, like at or below 2-3 picocuries, it may be enough to install a good air exchange system in your kitchen. But if the level are high, replacing your counter may be the prudent thing to do. But don't worry. Unless you've had these counter tops for decades, and work in the kitchen all day, you're probably perfectly healthy. However, limiting your exposure to radon is always a good idea. It is probably best to consult a professional to determine whether your radon levels are high enough to be a concern.

If you haven't bought granite yet, but are considering it, ask the supplier about radon levels. Find a responsible dealer that has invested in a geiger counter or scintillator. If the granite or marble dealer simply denies any risk, consider them uninformed. Of course they want to minimize the perception of risk. Their business depends on it. But a responsible business owner will test the product and only sell low to no-risk granite. That's who you want to buy from.