Rock salt, which is popularly called Sendha namak, in India. Sendha Namak / Lahori Namak or Rock Salt is considered light and calming in nature as compared to sea salt which is considered slightly heaty. It has no distinct flavor of its own so one does not miss ordinary salt and it can be used in the same quantities as ordinary salt. This along with the fact that is harvested from open mines makes it a viable substitute for salt in Fasting food.