Forsterite
Kojohama, Shiraoi city, Shiraoi county, Iburi branch, Hokkaido, Japan
Width: 10 mm. Forsterite in anorthite. The granular dark green crystal is forsterite. The surrounding white host is a cleavage surface of anorthite. The left edge of the anorthite is a crystal surface. The brown parts at the lower right is dirt.
Recovered from an anorthite phenocryst in a basaltic andesite lava erupted from a stratovolcano, a somma of a caldera. Formed in the Late Pleistocene (47 ka).
Forsterite from this location was described in 1964.
Other localities
- Hachijo Island (Placer, Olivine Sand)
- Hawaii (Placer, Olivine Sand)
- Lake Kuttara (Basaltic andesite, Granular)
- Usami (Andesite, Granular)
- Hayama Mine (Peridotite, Granular)