Birnessite
near Hawaii, USA
Source for manganese
Field of view: 20 mm. Fragments of manganese crusts overlying the ocean floor. The pyramidal crystals at the left are birnessite. Birnessite was formed by alteration of manganese hydrate, Buserite. Other massive black parts are composed of manganese dioxide. Manganese crusts and manganese nodules are studied actively because they are stocked under the sea near Japan.
Other localities
- Takaneyama Mine (Hydrothermal, Reniform)
- near Hawaii (Mn crust, after Buserite)