Excuse me my language but damn...
I had bought a mineral stone for Isa, as to the vet told me she needed it, because her jaw was a bit loose, even though she gets high quality food (all in one pellets).
The salt stone made sense for me as to the small size of a hamster but I honestly thought the others where okay/safe.
So thank you guys. I have taken it out of her cage, no more mineral stones for Isa.