How to cut open a Thunderegg
This YouTube video by Jared at Currently Rockhounding is the best reference for cutting open thundereggs.
Thunderegg Cutting Done Correctly // Geometric Pressure Ridges
Be sure to check out all the videos on the Currently Rockhounding channel!
It is definitely one of the very best lapidary channels on YouTube and Jared is also a fellow thunderegg enthusiast :)