From : Schweighausen, Black Forest, Germany
 
Dr. Liesegang rock is a silificated volcanic rock (Rhyolite) with beautiful reddish-brown and bright 
circle structures. The scientist Dr. Liesegang tried to explain the origin of these structures. 
This specimen is a polished slab with very decorative reddish lines just like a picture.
 
Dimensions : 15 x 10.5 x 1 cm