Life itself depends on salt, and people in early civilizations went to great lengths to acquire it. It was, and still is, used to preserve and season food, and it is important in medicine as well as religious ceremonies, all of which have made it a valuable trade commodity. Some early cultures even used it as a form of currency. All of this means that from ancient China to Egypt, Greece, and Rome, the history of human civilization is closely linked to the history of salt. Source: The History of Salt in Ancient Civilizations
Geographically close to China, in the area that would become modern-day Pakistan, a different kind of salt with a much older history was discovered and traded. Rock salt, also known scientifically as halite, was created from the evaporation of ancient inland seas and saltwater lakes, which left concentrated beds of sodium chloride and other minerals.
Himalayan rock salt was first laid down more than 500 million years ago, 250 million years before massive tectonic plate pressure pushed up the mountains of the Himalayas. But while early cultures living around the Himalayan mountains are likely to have discovered and used deposits of rock salt much earlier, the history of Himalayan rock salt starts with Alexander the Great in 326 BC.