The question is concerning a tongue piercing. Are there any types of jewelery of certain materials that would not be suitable for a new piercing, once it heals?
Well, I would recommend using only surgical steel, iodized titanium(which, yes, is already oxidized, but actually makes it safer), pure silver, titanium, platinum, and gold. Other metals can easily rust(speaking of which, DON'T use sterling silver, it rusts if you get blood, saliva, etc on it) causing damage and gross gunk to build up in your piercing. Plastic and rubber ends should be fine, unless you're allergic. I'm not sure about the rhinestone ones. Hope this was helpful!