> > The last stone: I think you missed one from the sandstone caverns (you'll just need to dig in a specific place).
> >
> > You have all the evidence you need, I think. Just try to show it to Johnson in the right order (if you show him something too early, he'll dismiss it and not even remember it when it turns out to be important).
>
> Thanks, I convinced him, and now he is waiting for a plan.
>
> For the last stone, how many times do I have to search at one place? I've been selecting "search the area for ores" five times in a row whenever I get the chance.
>
> kniv"With my luck, I'll probably have to search six times."etsil

Nope, you just need to search once. If you have a map of the sandstone caverns, you can just check off the locations one at a time (there are 16).