Rock salt is a pure form of salt that is generally found in the Himalayan region in higher concentration. Like common salt, it is not refined and present in its pure crystalline form. During the refining process of salt, many harmful chemicals are added to it to prevent salt from getting soggy. Rock salt is free from such chemicals therefore it can be consumed without having a side effect.
Rock salt formed when seawater or lake water evaporates and leave behind pale, transparent crystals of sodium chloride.
 
Health Benefits
Promotes Digestion
Boosts metabolism 
Boosts immune system
Relief from muscle cramps 
Treat sore throat 
Stabilize blood pressure