@justamom I have vegetative dystonia it doesn't make me afraid of anything but it causes other setbacks. The only thing I can suggest to you is to just care less , yes sometimes it is better to care less for the things around us than to care more because if caring more about any minor thing causes you to be stressed then trust me it will only lead to poorer health and less happiness long term.
I don't want to be judgemental but the way I see it , too many parents these days torture their kids with all kinds of made up dangers and they scare them. Kids even though they don't understand the language they feel the parents emotional state even better than we adults feel one another. In the long term I believe and actual studies have also concluded that our children are affected by the emotional background that their parents raised them up in. So I would suggest to you to not worry and actually work with your OCD because that will do you more harm long term than anything radiation related ever. This is a fact.
Remember what Roosevelt once said "The only thing we have to fear is fear itself". I knew a woman who had to learn this literally, her nerve problems prevented her from doing many simple things as she was afraid of them, like taking a train or a bus if it crossed a bridge anywhere etc. Irrational fear severely affects a person even to the point of premature illness and death.
Speaking about cancer and radiation. A human body has trillions of cells , cells constantly die off and new ones are created, statistically speaking this is a nightmare , hard to make any long term predictions out of a process that involves so many unknown variables. What I want to say with this?
The truth is that linking cancer to a specific cause , unless the cause is extremely obvious , like working in a asbestos mine, is very hard if not impossible. Cancer can be caused by lots of factors and not all people are equally susceptible to it. By the way, not enough sleep, stress and bad diet can also lead to it. By far I think this is a much bigger cause than anything radiation related. Tobacco is surely another proven danger.
Your tiny little dosimeter and your granite tops and mortar play no real role in all of this, you can be sure of that.
And in case you are afraid of green rocks, well you now have a dosimeter I suggest you use it , but not out of fear but for learning purposes and curiosity. Take a reading of the rock, if nothing changes you know it's not Uranium...One other thing you should know. Naturally radioactive ore or elements are not really dangerous, unless you eat them or try to use them as table salts, elements only really become dangerous once they have been irradiated/underwent a nuclear reaction. Stuff like spent fuel, reactor core parts etc.
Trust me you will not come across them in your entire life even if you wanted to.