Gratonite
Ikarigaseki, Hirakawa city, Aomori pref., Japan
This locality is closed to collectors.
Field of view: 5 mm. Gratonite associated with jordanite. The prismatic crystal is gratonite encrusted with white clay. The surrounding host is jordanite covered with white clay.
Recovered from an open space of a sulfide vein in a moderate-temperature hydrothermal deposit associated with rhyolitic welded tuff in a caldera complex. Formed in the late Pliocene (3.5 Ma).
The first gratonite from Japan was reported from this location in 1984.