Nope. I would inform a geology firm who will then contact some magazine people and we would quietly talk to the owner. They won't get the money due to having science analyzing it but the press can high light anything the owner wants.
Is the person who owns the property already insanely rich? A nice person or a creep? Did he make all his money on **** or because he bumped off his wife? Or the reverse if it's a "she"?
I'd probably alert the owner to what I'd found.
By the way, what am I doing on private property?
seeing the other answers i clearly have no morals