Abstract
The writer has studied the occurrence of the gypsum deposits accompanied by the Kuroko (Brack ore) deposits. The conclusions are follows.
1. The hydrothemal gypsum deposits of the Wanibuchi mine occur as the bedded deposits. But they do not exist in the same horizon.
2. The crystallization stage of the spherical or massive anhydrite is earlier than that of the metallic minerals.
3. The anhydrite alters to the gypsum by hydration, as the temperature falls.
4. The stage of the formation of gypsum vein is same as the hydration stage.
5. The volumetric changes are caused by the hydration of anhydrite.
