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Washinosu Mine

Nishi-Waga city, Waga county, Iwate pref., Japan

This locality is closed to collecting.


Moderate-T hydrothermal deposit

Moderate temperature hydrothermal deposit in rhyolite lava and dikes in middle Miocene (15.4 - 13.6 Ma) Kawashiri Tuff Member, a top member of early - middle Miocene (16 - 13.6 Ma) Oishi Formation. These rhyolite lava and dykes form a submarine lava dome. Ages of sedimentary rocks were determined by microfossils.

Washinosu Mine

Outcrop of oxidation zone of Cu deposit. The green color is attributed to chlorite formed by alteration of rhyolite and rhyolitic pyroclastics of Oishi Formation. So called "Green Tuff", Japanese Tertiary sediments, was named after this.

Reported Minerals

  • Pyrite
  • Chalcopyrite
  • Malachite
  • Cuprite

Details of the mine

Cu was mainly mined, and Au and Ag were also produced.


  • 1095: The legend says that this mine was developed in Kamakura era by Fujiwara family, who run local government in this area.
  • 1901: Takichi Fukazawa rediscovered the deposit.
  • 1903 - 1915: The Au deposit was mined.
  • 1915 - 1963: The Cu deposit was mined.
  • 1963: The mine was closed.
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