Such mineral displays are common...but not necessarily actinics, IME. They are frequently shown under UV lights to highlight flourescent minerals.
Geodes, IMO, have no place in a reef and would basically just be a place for a bunch of detritus to accumulate. Not to mention that there are minerals in many that would be potential impurities in the tank. I defintiely wouldn't do it.
IMO, leave the minerals in your mineral display and reef rocks in the reef tank.