Tiny Tuesday - 'I is for Inside'

This is an attempt to photograph the inside of a geode.
A geode is a hollow rock with sparkling crystals inside. They are formed in various ways, but basically it is to do with gas bubbles trapped in rock during volcanic activity.
I illuminated this one from the rear with a torch to try and get the crystals to sparkle. It's a bit tricky without a macro lens too!