Magnetite

Otaki, Chichibu city, Saitama pref., Japan

Source for Iron

Field of view: 5 mm. Magnetite associated with garnet skarn. The black grains are magnetite. The white part around magnetite is calcite. The brown host is aggregate of andradite grains.

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).

Magnetite from this location was described in 1930.

Field of view: 100 mm. Magnetite pseudomorph after platy hematite. The black platy crystals are magnetite. This was formed by the change of oxidation state such as oxgen fugacity. The yellow parts are pyrite.

Other localities

List of Japanese magnetite localities

Chichibu Mine (Hydrothermal Skarn, Granular)
Asemi River (High-P metamorphic, Octahedral)
Hase Mine (High-P metamorphic, Octahedral)
Onara (Serpentinite, Granular)