Cryptomelane?
Yatsuhashi, Shitara city, Kita-Shitara county, Aichi pref., Japan.
This locality is strictly closed to collecting.
Field of view: 10 mm. Cryptomelane(?) in an open space of the aggregate of rhodonite and quartz. The reniform black crust is probably cryptomelane. The reddish-brown part at the bottom is the host, aggregate of rhodonite and quartz. The white parts at the top is dirt on the surface.
Recovered from a meteoric oxidation zone of a bedded manganese deposit in pelitic schist subjected to Amphibolite facies regional metamorphism and contact metamorphism by granodiorite.
Cryptomelane from this location was described in 1993.