The stone is probably Cinnabar, which was thought to have mystical properties and could grant immortality. In reality, it was an ore of Mercury and gave people slow mercury posioning.
Why is there a dad in the last panel? Did the artist forgot their own story? The kid can be excused, as they need to be raised somewhere, and maybe they are deported at a certain age.
Glad they didn't drag it out. I can imagine a worse author having 10 more chapters where the audience obviously knows much more than the main character.