Köpfchen Thunderegg with a Core Filled with Debris

8.5cm

This is the sort of thunderegg that I can go nuts over! Not necessarily the finest agate banding or brightest crystals, just a specimen that has done something really cool and kind of unusual.

Köpfchen thundereggs are a rather 'rough-and-ready' type, often colourful, strange and highly flawed. This one has pretty much burst, at some point in its life long long ago. It split open after the white agate layer was formed and the hollow interior became filled with debris from outside, which became 'frozen' into solid stone (Silicified mud?). Not so unusual, but the fun part here is how well the flow and movement have been preserved, as the materials streamed in and were deposited in layers. The dark cracks, which you often see in this location, presumably happened later on as more stress fractured the stone further.

Every stone has a story in that you can read. :-)