Manganite?

Field of view: 10 mm. Probably manganite. The fan-like groups of black acicular crystals with a metallic luster are probably manganite. The reddish-brown host is hematite-rich chert. The white part at the lower left is a quartz vein.

Recovered from a meteoric oxidationzone of a chert-hosted bedded manganese deposit subjected to Pumpellyite-Actinolite facies metamorphism.