Thank you for your response. That was my first thought. The metal rod does go all the way through the stone. If it is some sort of dentistry it is rather ingenious. Thought it could be some kind of fishing weight but growing up on my grandfathers head boat out of Cape May it did not resemble any thing I saw and I saw a lot of funny rigs.. If it is dental I’m sure glad that profession has advanced.
Is the metal part definitely lead (or primarily lead)?
Can you tell (specifically) what material the white part is?
FWIW, doesn't look dental to me.
Could it be a teeth ?