Hyalite
Hirukawa
Hirukawa, Nakatsugawa city, Gifu pref., Japan
This locality is closed to collectors.
IMA approved name
Opal var. hyalite
Field of view: 3 mm. The reniform transparent group is hyalite. The black basement is a prism of black quartz.
Recovered from a pocket of a Topaz-NYF pegmatite associated with S-type (Ilmenite-series) granite. Formed in the Late Cretaceous (67 Ma).
Hyalite from this location was described in 1939.