I once attempted to inhabit a crystal during a real-time AP. It didn't work out quite like I'd hoped... It was a double terminated quartz, pretty standard, but I figured since I'd always found quartz to be great at storing energy, it would logically be the best choice.
In that attempt, I didn't really find the quartz crystal to hold any seriously special properties. I thought it might give the illusion of having more space within it, inhabitable in some way, but it really didn't... I simply moved through it in the same way I do most solid material in AP. I didn't try anything very special to get into it either. I suppose it would be interesting to experiment more, but I don't really know to what end research like that would help.
In that attempt, I didn't really find the quartz crystal to hold any seriously special properties. I thought it might give the illusion of having more space within it, inhabitable in some way, but it really didn't... I simply moved through it in the same way I do most solid material in AP. I didn't try anything very special to get into it either. I suppose it would be interesting to experiment more, but I don't really know to what end research like that would help.