DIRK WIERSMA / SCIENCE PHOTO LIBRARY DIRK WIERSMA / SCIENCE PHOTO LIBRARY
Psilomelane. Botryoidal form of the mineral psilomelane, an ore of manganese. Psilomelane composed mostly of the mineral romanechite, a barium manganese oxide mix. Here, botryoidal refers to the grape-like shapes, which formed due to underground hydrothermal (hot water) processes. Manganese is a valuable metal since it is an essential ingredient in steel and other alloys. The height of this sample is 11 centimetres.
Model release not required. Property release not required.