Athiests what would you do in this situatation i dont have a religion or go to church or belive in anything?

I would probably explain to my child that there are people that *believe* that such things can protect them. I would also explain that while such thoughts are comforting to the people that believe them, in reality such necklaces offer no more "protection" than any other necklace. I would let them keep the necklace if they wanted it.