Monk Fyv closes his eyes and concentrates
really hard.

Nope. No spontaneous combustion. Maybe Monk Fyv should try
planned combustion?

Monk Fyv picks up the gem, and puts it in his pocket. As he does so, he notices that his pocket also contains a piece of twine, about the length of his arm.
A thorough search of the gobwin reveals nothing of interest or use, though from that location he notices that the cave extends around behind the sign - there seems to be a passage back there...
What now?