Jacobsite
Nippara, Okutama city, Nishi-tama county, Tokyo, Japan
Field of view: 10 mm. Jacobsite associated with hausmannite. The black vein traversing from left to right is aggregate of fine jacobsite crystals. The surrounding massive dark brown parts are aggregate of fine hausmannite crystals. The white to pale pink vein at the top is Rhodochrosite.
Recovered from a chert-hosted bedded manganese deposit subjected to weak Prehnite-Pumpellyite to Zeolite facies metamorphism.
Jacobsite from this location was described in 1980.
Other localities
- Kurokawa Mine (Mn skarn, Band)
- Kiyokawa Mine (Bedded Mn, Zeo facies)
- Gozaisho Mine (Mn Skarn, Iwakiite)