Sendha namak, a type of salt, is formed when salt water from a sea or lake evaporates and leaves behind colorful crystals of sodium chloride. It's also called halite, saindhava lavana, or rock salt. In Ayurveda it is considered as healthiest form of salt. Rock salt or commonly known as "Sendha Namak" is the purest type of salt which is devoid of any chemical components and environmental pollutants. It consists of 84 natural minerals and nutrients that are essential for the human body. 

Origin: India