Tag Archives: crystal habit

Geopic of the week: Manganese Dendrites


This is a picture of a sedimentary rock called novaculite collected in the Ouachita Mountains of central Arkansas.  On the surface are thin coatings of a manganese oxide mineral in shapes reminiscent of trees.  When a mineral forms in these tree-like patterns, it is called a dendrite (named for the impulse-transmitting nerve component of a similar shape).  Manganese oxide minerals commonly form in this peculiar morphology.

For more views of manganese dendrites click here