Answer:
A dragon's tooth in a mortal's hand, I kill, I maim, I divide the land.
The ones who see it may go blind, Contracting the fool's madness. You have to dig to find it, Crush big stones or mine it. Wash dirt clumps in a pan and wait for it to settle, A shiny, precious metal.
Bury deep, Pile on stones, My mind will always Dig up them bones
My sides are firmly laced about, Yet nothing is withinΝΎ You'll think my head is strange indeed, Being nothing else but skin.
It is sometimes known to have silver linings.
I am your mother's brother's only brother in law. Who am I?