They are very hard but I have never lost one. I after the first one I started wearing a tight glove on my left hand. Those shards and seeds can draw blood quickly. I made a bud vase and several other items and always just turned between centers.
As hard as the pods are I don’t think I want to try a goblet. I assume you will turn the goblet and stem and then use a different wood for the base?
I have one I never finished so I may use it to make a Christmas ornament. It is just a two inch ball now. I was going to mount it on a pedestal and turn rings (maybe what Saturn would look like from Australia).
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety. Benjamin Franklin