Firstly, I have no clue what this wormlike mass of tunnels and curves could have been before replaced, but we think it to be a goethite or limonite replacement pseudomorph now. What it was originally is anybody's guess. The piece is solid, all-around, made up of these hollow tubes and curving growths. It looks like 20 shoelaces dipped in glue and hematite powder, twisted in loops, and left to dry in the sun. An interesting, and apparently older specimen from the Erongo Region, and from the noted Erongo specialty collection of Heini Soltau.