Yoshimi-Hyakuana
Yoshimi city, Hiki county, Saitama pref., Japan
Occurrence
Sulfate minerals growing on the rhyolitic tuff surface of Hatakeyama Tuff Member of Arakawa Formation.

Outcrop of Hatakeyama Tuff Member of Arakawa Formation. The reniform group of white alunogen is on the surface of rhyolitic tuff. The gray basement at the upper left is tuff. White bubbly structure on the surface is aggregate of sulfate minerals such as alunogen. Sulfate minerals crystallized when dissolving water in tuff evaporated in a dry climate.
Reported Minerals
- Alunogen
- Gypsum
- Alum
- Jarosite
- Thenardite
- Epsomite
- Halotrichite
- Tamarugite
- Hexahydrite
Mineral Assemblages
- Alunogen - Alum - Jarosite - Thenardite
- Hexahydrite
Localities
- Yoshimi-Hyakuana (Alunogen)
- Sagiri valley (Pickeringite)
- Iwadono Kannon (Epsomite)
- Oya (Mirabilite)
- Oya Quarry (Mirabilite)
- Desert Cave Hotel (Filiform gypsum)