Halite is the mineral name for salt, or sodium chloride; it's referred to as rock salt when in rock form. Halite is typically either white or clear in color, but it can have a range of different colors including blue, violet, pink and yellow due to impurities. Halite forms through the evaporation of sea water over a long time period, and it is considered to be a sedimentary mineral.
Halite can also form near lakes from the evaporation of brine water. These salt deposits are typically found along salt lakes in arid regions, such as near Salt Lake City, Utah. In areas that are not arid or dry, halite is found in deep underground beds. Its Mohs hardness is 2.5, and its chemical formula is NaCl. Its specific gravity is about 2, and its crystal system is isometric.
Humanity's use of halite dates back to 3000 B.C. In ancient times, it could be used for cooking purposes or the preservation of meats or other foods. Today, halite in the form of rock salt is used to deice highways and sidewalks during the winter. It is also used in the pharmaceutical and chemical industries and can be used to make ice cream.