In several situations in Ultima IV someone has told me to ask a bartender about something (e.g. ask at the Tap in Trinsic about the "stone"). However, when I talk to the bartender I can only buy food or ale. How do you ask them questions? Am I doing something wrong?

It worked! Thanks a lot!

Go to a Guild Shop (Buccaneer's Den or Vesper) and ask for item D on the list of items they sell. It isn't part of the regular menu, but they'll sell it to you if you ask for it.

I know, i know, thanks! I've meant a way to KNOW that there is such an item, hence legit. But i've already met someone in my travels who told me to ask for it. ;)