Rock salt is the more common name for halite, which as the name suggests, is a rock and not a mineral. It can be found all over the world, especially in arid regions and salt has been used to flavor food for thousands of years. Because salt and water combined have a lower freezing point than water, halite is often used to spread on snow or ice to melt it. Many towns and cities around the world use tons of halite each winter to melt ice or improve traction for drivers, although even a small amount of rock salt is highly effective.
Rock salt is sometimes also used in farming. One of the most common uses is its use in the production of turf, to control and restrict the growth of meadow grass. Small particles of halite are also sometimes used as ammunition, as it is considered more humane than other forms of ammunition.