Piemontite
Kitagawa, Hanno city, Saitama pref., Japan
Field of view: 5 mm. Piemontite associated with braunite. The acicular reddish-brown crystals are piemontite. The opaque white to transparent parts with a vitreous luster are a quartz vein. The massive black parts are aggregate of fine braunite crystals.
Recovered from a chert-hosted bedded manganese deposit subjected to Pumpellyite-Actinolite facies metamorphism. Formed in the Late Cretaceous (100 Ma).
Piemontite from this location was described in 1982.
Other localities
- Asemi River (EA facies, Prismatic)
- Nagatoro (GS facies, Prismatic)
- Tone Mine (GS facies, Prismatic)
- Iwaisawa Mine (PA facies, Prismatic)
- Kusama Mine (Zeo facies, Prismatic)