Bockelwitz Thunderegg with Ice-Like Quartz Core

As the only specimen I have seen, it is hard to say how characteristic it is, but that matrix immediately jumps out at you.  It is like other Saxony stones, but more so - much more so, being packed full of large crystal grains and what look like hollows where crystals once were.  It is the most open and sponge-like matrix I have ever seen.

The core is also interesting.  A thin band of agate surrounds what I take to be pure quartz, much of it water-clear.  It was nearly impossible for a photograph or a scan to reveal just how clear that is but parts of it are literally like glass.  Clearer than any agate I have seen, it is the clearest solid matter I have ever seen in a thunderegg.  The whole core looks as though it is made of ice.

I am surprised just how fascinating this stone is!  I cant stop looking at it.  Sadly it is maybe one that has to be experienced in the flesh, but I hope interesting nonetheless!  

8cm