Sometimes appears on labels as "Shinshiro mine" or "Yoshikawa mine". The true Yoshikawa mine is another locality in the same city. Copper and nickel minerals in a serpentinized gabbro that was worked for copper for only 3 months in 1953. Very dangerous, long-abandoned quarry with overhanging ledges of unstable fractured rock.
Ref:
Am.Min. 62:594 (1977)