It is a rock salt ingested by the salt formations at the foot of the Himalayas. The rock salt is used as a raw material, and through the baking process, it becomes black rock salt containing sulfur components. When placed in water, the sulfur ground and natural minerals dissolve, giving off a peculiar sulfur smell, and you can feel the moist water. You can enjoy the feeling of a hot spring with the scent of sulfur at home.