I have a small piece of rock inside the palm of my hand. The largest diameter is probably less than 3 mm, and it generally doesn’t bother me (except if I’m unlucky in how I grip something, or start pushing at it too guess at its size :D). It’s mostly likely either granite or gneiss.
Are carcinogens slowly leaching into my body?
Am I going to suddenly die from this? It’s been in my hand for about … 26 … years.
When you can snatch the pebble from your hand, it will be time to go, grasshoppah.
Other than the pain, if after 26 years it hasn’t gotten infected, I’d bet you’re fine. IANAD.
FWIW, I once had a sliver of glass in my finger for a few months, and other than the searing pain, I had no infections (thankfully!).
A few stiff drinks and some home surgery fixed me up. but I certainly wouldn’t recommend it.
Other than that, I agree with Cal. 
-Butler
Well, granite is pretty inert chemically, at least in the context of being embedded in your skin, but it can emit radioactive radon gas - I can’t say whether this poses any kind of appreciable risk to your body, given the small size of the thing (if it is indeed granite at all).
You may want to ask the doc to remove it for you if it looks like its close to the surface. No need to go around worrying about how you grip things.
The same thing happened to my uncle and 50 years later he died. I’d be careful…
Have you run a radon detector over the spot?
I fell down a hill onto a dirt road and broke my fall with my hand, lodging a tiny rock beneath my skin. Five years later, it came out. I still have a little hole in my hand where it exited. This was over 15 years ago.
If the piece suddenly worked its way into a vein and was transported throu your circulatory system to be lodged in an artery, you could end up with a heart attack or a stroke.
Have a nice day. 
What puzzles me is how it’s taken you 26 years to start worrying about it. :dubious:
For the first 15 years I almost forgot it was there. Then I had fun telling people about it and showing them. And then I started worrying. But I worry about practically everything, so I so no reason to ask anyone. I only asked because I was bored though. And now I regret it. Must have hand checked with geiger counter. 
You may slowly turn into The Thing but apart from that I think you are pretty safe. Perhaps you should start working on some nifty superhero catchphrases just incase.
My mother had a small bit of coal in one of her hands. It never gave her any problems. I’ve had a pencil point in my left palm (I think it’s still there; I can’t see it anymore) since I was a kid. I’m 54 now.
I had a pencil point (still on the pencil) got lodged in the palm of my hand right below the index finger… its been there for about two years… no problems… yet… ::nervousily looks around for some wood to knock::
IANAD , nor do I play one on TV, but I think you’re probably alright.
A chunk of lead (bullet, debris from bizarre fishing sinker accident) might be cause for concern, though.
