Montmorillonite
Kodomari, Nakadomari city, Kita-Tsugaru county, Aomori pref., Japan
Source for bentonite
Field of view: 50 mm. Massive montmorillonite. The network of white veins is pure aggregate of fine montmorillonite crystals. The gray parts contain impurities. The specimen shows that andesite, the protolith, has been altered along fracture networks.
Recovered from andesite subjected to hydrothermal smectitization alteration.
Montmorillonite from this location was described in 1970.
Other localities
- Bentenzaki (Smectitization, Massive)
- Morocco (Smectitization, Massive)
- Hirasawa (Alpine Fissure, Pink)