Then the self-oscillation (spin-precessuion oscillation) of probably the quartz is transferred via the Overhauser effect to the other half- and rare earth metals and that creates an interactive spin-precesion oscillation, which leads to the low current oscillations (in comparison to the molecular oscillation) in the whole set-up. That is why your set-up sometimes oscillates. I have the same with my cells.
Great stuff what you are doing.. project is to make these simple to build for you folks so that why i
seek money to try to do this like the very successfull open sourced crystal power cells you folks are building now on youtube you tube search crystal power cell now is time to do the same for this unit thanks and god bless