Glowing Gandalf staff

Hi, I am looking to make a prop for my Halloween costume. I want to find a tree with some little gnarly roots on the end to make a Gandalf staff. I want to bore a hole from the top straight down and insert batteries and a light of some kind, then put a crystal-like rock on top to simulate the glowing rock Gandalf uses for light in Moria.

Now, any suggestions as to how to set this up? I can't drill a big enough hole for anything larger than AA's or so. I am thinking maybe an LED light, because I want to have enough runtime to keep the light on while taking the kids trick-or-treating.

Any ideas would be welcome. I already have a perfect rock... It is actually a chunk of waste from a glass plant but it looks like a chunk of crystal or quartz. I have not found a good-looking staff yet either, any ideas? I was thinking a dead sapling or something but I'm not sure what kind of tree. Pine roots dont look right so far. Thanks for any ideas you might post...

I'll suggest a DB400 with 6 or 8 AA batteries in series along with a 1 watt LS or 10 overdriven nichias or 20 normal driven nichias. I think you should go the nichia way because you won't have to bother about heat. Best to drive 20 of em at spec.

I would just use 2 or 3 6000mcd white leds. I have lit up many quartz clusters and points... and I find 1 does fine. Use 3 if ya want and drive them at rated current. Position them right at the base of the crystal or glass...pointing straight up through it.