with yamagata-ken chokaisan obsidian ?

Minerals collected at the foot of Mt. Chokai in Sakata City, Yamagata Prefecture? is.
?? Is attached because it is a little unclear whether it is a mineral.

Since there are natural traces of lava melting and chilling and overlapping, which is a characteristic of general obsidian, I decided to take it home as an obsidian, so the collection location is at the foot of Mt. Chokai. Not.

size
Width 2.7 cm
Height 1.5 cm
Height 1 cm

Origin: Sakata City, Yamagata Prefecture The quay at the foot of Mt. Chokai
Stone material: Obsidian? (Glass made by cooling lava)