Halite: Salt of the Earth

     Halite (which is also called “rock salt”) is chemically the same as common table salt. What differentiates halite from the stuff in our salt shakers is its form and color. Halite grows as large, cubic crystals that are often found growing together as large conglomerate masses. In addition to the cubic shape that the halite crystals usually display they have also been found as octahedrons, and fibers. Halite has also been found as encrustations, stalactites, and hopper crystals. A hopper crystal occurs when a crystals edge grows faster than its face. This results in a crystal that has stepped depressions all over its face. Halite most commonly smoky gray in color, but when absolutely pure it can be white or clear. Impurities can cause it to be red, pink, blue, purple, yellow, orange, and green. Most of these colors are usually very pale, but purple and blue can show very strongly. Like all salt, halite dissolves in water, so if you have any in your collection don’t let it get too wet!
     When thinking about what possible uses there could be for the mineral halite, remember that it is salt and is used in every way that one would use salt. Halite is, of course, used to flavor food and was once used to preserve meats. Halite is also a major source of the salt that places with colder climates use to keep their roads from icing. Halite is also used as a source of the metal sodium which is used to make lye (sodium hydroxide.) It is also used to purify water and in modern food processing.
I have personally seen halite do some interesting things. I once grew a stalactite of salt that was hollow and had angular sides. It was about two and one half inches long. Also, in Acadia National Park, Maine I found a puddle that appeared to be frozen, but when I touched it I found that the white covering atop it was actually crystallized salt!
     Halite is found in many places on the earth, the seashore being the most notable. It is an evaporate (a mineral that crystallizes as the result of evaporation.) Fine specimens can be found in California. Large halite deposits can be found underground as well. There are famous salt mines in Poland and beneath Detroit. There are also mines in New York state. The Great Salt Lake in Utah is a good source of evaporate salt as is the Dead Sea in Israel.
     Halite’s name can be a little misleading, but I don’t mind. It is important to science, the food industry, road safety, and many other such things. Who would have thought that salt can be so important?