Gnocchi is a very tricky dough. The key is to control the moisture of the potatoes. Gnocchi dough is soft and delicate, and the trick is to make just enough gluten when kneading to hold everything together—but not too much, or your gnocchi will turn into rocks. If the dough does not feel right, there may be too much moisture in the potatoes from the season when they are picked—we call these "bad gnocchi potatoes"; you may have to adjust the flour to help the dough out.