Todorokite

Field of view: 10 mm. Todorokite associated with birnessite. The plumose dark brown group is todorokite. The reniform black group with a dull luster at the right is birnessite.

Recovered from a quartz vein in a moderate-temperature hydrothermal deposit associated with andesitic to basaltic pyroclastic rocks of an oceanic arc subjected to propylitization alteration. Formed in the late Miocene (7.5 Ma).

Todorokite from this location was described in 1981.