When I was being taught geology the lecturers would occasionally lick a rock. I still don’t know if it was a joke as most rocks taste pretty neutraock If you are interested, give it a lick, it can’t do you any harm. Although bear in mind that limestones are a broad church, so you may need to lick a few to get an idea of the breadth of their taste nuances.

Unless a rock contains ores then they are usually OK to taste so branch out after that.