Amygaloidal Graphite from the Oshirabetsu mine, Hiroo, Hokkaido, Japan

Spheroidal Graphite in gabbro. (right: cut section). John A. Jaszczak collection and photos.

References:
Tsuchiya N., Suzuki S., Chida T., [Origin of graphite in the Oshirabetsu gabbroic body, Hokkaido, Japan] Ganko [Journal of Mineralogy, Petrology and Economic Geology] 86(6) (1991) 264-272. [In Japanese with English summary.]

Shibata Y., Matsueda H., and Yui S., [Texture and mineral paragenesis of orbicular graphite from Oshirabetsu, Hokkaido], Kozan Chishitsu [Mining Geology] 41(3) (1991) 185. (Abstract. In Japaneze).