This stone has broken into two pieces:
It looks like someone has repaired it before, which complicates matters. First an external clamp is made so that the parts can be squeezed together.
jig made and dry fit done, ready for the stone to be cleaned and glued.
There are new epoxy adhesives that have been developed specifically designed to integrate with the structure of specific materials. This is the approach I am taking in order to maintain resonance.