Thomsonite-Ca
Heguri-naka, Minami-Boso city, Chiba pref., Japan
Field of view: 10 mm. A group of thomsonite-Ca. The group of platy white crystals is thomsonite-Ca. The massive light brown part at the upper right is the host tuff.
Recovered from a vein of thomsonite-Ca in an accretionary complex subjected to Prehnite-Pumpellyite facies metamorphism.
Thomsonite-Ca from this location was described in 1982.