The Salt Institute is dedicated to advancing the many benefits of salt, particularly to ensure winter roadway safety, quality water and healthy nutrition.
The benefits of salt, or sodium chloride, have been known to man for thousands of years as evidenced by ancient salt mines the world over. At the Salt Institute we receive many queries about the chemical nature of sodium chloride, where salt comes from, how it is produced and mined, and how much salt get produced and shipped each year. We are also asked how all this salt is used and how it is divided up between road, commercial, medical, manufacturing a food uses.
To help answer these questions the Salt Institute has gathered the additional external references below, offering comprehensive information about the salt industry and the history of salt:
The U.S. Geological Survey, part of the U.S. Department of the Interior, publishes annual Mineral Commodity Summaries andYearbooks, as well as other special publications that offer in-depth discussion and historical statistics about salt.
Salt: A World History by Mark Kurlansky (2003)
The only rock we eat, salt has shaped civilization from the very beginning, and its story is a glittering, often surprising part of the history of humankind.
For all things “salt,” you’ll want to visit the Mr. Bloch Salt Archive “Salt Made the World Go Round.”
For another fine, streamlined summary, see the Environmental Literacy Council.
Salt is rarely dated, so these older books are still valuable, though the Kaufmann book is out of print:
The Columbia Encyclopedia not only has further background information, but also a YouTube video clip on the solubility of sodium chloride.
The Wikipedia entry for “sodium chloride” has effective artwork on the right margin.
Andrew Alden’s article “About Salt” is excellent, particularly his discussion under “salt tectonics” about the salt glacier in Iran.
The properties of sodium chloride are well-summarized by Crystran Ltd.
Online Periodic Tables of the Elements give good background on sodium and chloride (and the other elements, naturally). Take your choice:
The structure of the salt crystal is often used to illustrate principles of crystal formation. Here are some good graphic examples of salt’s crystal structure:
Salt crystals are fascinating photo subjects. Some of the best are online courtesy of Cal State-Hayward and the Institute for Mineralogy and Mineral Resources at the Technical University of Clausthal, Germany. GeoKansas has a photo of a large crystal from Hutchinson, KS. The Museum of Science, Boston has a highly-magnified photo of kosher salt.
Sodium chloride crystals exist due to ionic bonding. John Blamire of Brooklyn College (NYC) explains this basis for salt’s physical structure. A page put up by Cornell University explains how salt crystals can explains how salt crystals can be modified by temperature.
Many online science pages offer instruction on growing salt crystals. The best are those by
Vast quantities of salt comprise 3.5% of the weight of the oceans of the world. The Smithsonian Institution explains why the oceans are salty. Some salt is one the surface, the dried-up residue of ancient seas like the famed Bonneville Salt Flats in Utah.
Most of the salt used in North America, however, comes from underground salt deposits which are of two types: domal and bedded (or sedimentary). Get a tutorial – and view some outstanding graphics — about underground salt deposits at The Salt Mine by the Bureau of Economic Geology at the University of Texas.
Salt deposits are ancient, about 400 million years olds. Salt deposits have been found to have encapsulated ancient microorganisms including bacteria. Salt even arrives on earth from outer space in meteors and its presence on the planet Mars makes scientists think life may exist there (in fact, scientists speculate that salt-loving bacteria live in underground water on Mars — as they have survived in suspended animation for 250 million years in Texas).