And so the search continues. For quite some time.
Eventually even the patient Tonbokiri has to admit that there seems to be nothing to find.

"I am sorry that we did not find anything today, Asano-dono. Perhaps the Stone is harder to see than we first thought. It would not be a quest if it were easy, after all. Let us go home for now, and try again another day."

There was those chemistry things they'd come across, but... he simply cannot imagine how finding the stone and that could be connected.