Halite is the scientific name of ROCK SALT, the question is “how is Rock Salt formed?”; it is true, ROCK SALT is formed from SODIUM CHLORIDE, It's chemical formula is NaCl.
The most important factor which distinguishes ROCK SALT from MARINE SALT is the appearance and mechanism of composition, ROCK SALT forms isometric crystals and it is typically colorless or white, but may also be other colors depending on the amount and type of impurities contained within it.
The rock salt is found in beds of sedimentary evaporate minerals. This is caused by large lakes and seas drying up. These salt beds can be hundreds of meters deep. ROCK SALT crystals form very quickly in some rapidly evaporating lakes. SIWA in EGYPT was covered by inland seas over 200 million years ago which helped create the layers of salt that are mined today. When very hot temperatures in the area evaporated the waters very slowly, they left large salt deposits under the earth. Then through the long process of geologic aging, the salt layers are covered with marine sediments.
Unlike traditional rock salt, white marine salt is not mined from underground. Instead it is harvested by evaporating sea water, which leaves behind a cleaner product.
The color of ROCK SALT crystals is geologically influenced going from clear, to pink, to dark brown.