Ilvaite
Otaki, Chichibu city, Saitama pref., Japan
Field of view: 50 mm. Crystals of ilvaite. The black prisms with a resinous luster are ilvaite. The surrounding translucent white host is gangue quartz.
Recovered from a quartz vein in 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).
Ilvaite from this location was described in 1954.
Other localities
- Chichibu Mine (Hydrothermal Skarn, Prismatic)
- Horado Mine (Hydrothermal Skarn, Granular)
- Obira Mine (Pneumatolytic Skarn, Prismatic)
- Kamioka Mine (Pneumatolytic Skarn, Granular)