Johannsenite
Otaki, Chichibu city, Saitama pref., Japan
Field of view: 20 mm. Crystals of johannsenite. The columnar group of translucent pale bluish-green prisms is johannsenite. The black grains exhibiting perfect cleavage are sphalerite.
Recovered from a moderately low-temperature hydrothermal deposit combined with skarn formed by contact metamorphism of I-type (Magnetite-series) quartz diorite. Formed in the late Miocene (6 Ma).
Johannsenite from this location was described in 1964.
Other localities
- Chichibu Mine (Hydrothermal Skarn, Prismatic)
- Akatani mine (Metasomatic Skarn, Prismatic)
- Kawazu mine (Hydrothermal, Prismatic)