Halite






General


CategoryHalide mineral


Chemical formulaSodium chloride NaCl


Identification





Colorclear or white; also blue, purple, pink, yellow, and gray


Crystal habitpredominantly cubes and in massive sedimentary beds, but also granular, fibrous and compact


Crystal systemisometric 4/m bar 3 2/m





Cleavageperfect in three directions





Mohs Scale hardness2 - 2.5


Lustervitreous


Refractive index1.544











Streakwhite


Specific gravity2.1














Solubilityin water





Other Characteristicssalty flavor










Halite is the mineral form of sodium chloride, NaCl, commonly known as rock salt. Halite occurs as cubic crystals that are typically colorless to white, but may also be light blue, dark blue, or pink. It commonly occurs with other evaporite deposit minerals such as several of the sulfates, halides, and borates.

Contents

1 Occurrence
2 Salt domes and glaciers
3 Unusual formations
4 See also
5 References
6 External links
7 Credits



Occurrence
 Halite crystal from Germany
 Halite (middle) and other salt minerals
Halite occurs in vast beds of sedimentary evaporite minerals that result from the drying up of enclosed lakes, playas, and seas. Salt beds may be up to 350 meters (1150 feet) thick and underlie broad areas. In the United States and Canada extensive underground beds extend from the Appalachian basin of western New York through parts of Ontario and under much of the Michigan basin. Other deposits in the region are in Ohio, Kansas, New Mexico, Nova Scotia, and Saskatchewan.

Salt domes and glaciers
Salt domes are vertical diapirs or pipe-like masses of salt that have been essentially "squeezed up" from underlying salt beds by mobilization due to the weight of overlying rock. Salt domes typically comprise anhydrite (anhydrous calcium sulfate, CaSO4), gypsum (CaSO4·2H2O), and native sulfur, in addition to halite and sylvite (potassium chloride (KCl)). They are common along the Gulf coasts of Texas and Louisiana and are often associated with petroleum deposits. Germany, Spain, the Netherlands, Romania, and Iran also have salt domes. Salt glaciers exist in arid Iran, where the salt has broken through the surface at high elevation and flows downhill. In all these cases, halite is said to be behaving in the manner of a rheid.

 Large natural crystal of Halite, showing cubic cleavage breaks.
Unusual formations
Unusual, purple, fibrous veins running through halite crystals are found in France and a few other localities. Halite crystals termed hopper crystals appear to be "skeletons" of the typical cubes, with the edges present and stairstep depressions on, or rather in, each crystal face. In a rapidly crystallizing environment the edges of the cubes simply grow faster than the centers. Halite crystals form very quickly in some rapidly evaporating lakes resulting in modern artefacts with a coating or encrustation of halite crystals. Halite flowers are rare stalactites of curling fibers of halite that are found in certain arid caves of Australia's Nullarbor Plain. Halite stalactites and encrustations are also reported in the Quincy native copper mine of Hancock, Michigan.

See also
Sodium chloride
History of salt
ReferencesISBN links support NWE through referral fees
Farndon, John. The Practical Encyclopedia of Rocks & Minerals: How to Find, Identify, Collect and Maintain the World's best Specimens, with over 1000 Photographs and Artworks. London: Lorenz Books, 2006. ISBN 0754815412
Klein, Cornelis, and Barbara Dutrow. Manual of Mineral Science. 23rd ed. New York: John Wiley, 2007. ISBN 978-0471721574
Kurlansky, Mark. Salt: A World History. New York: Penguin, 2003. ISBN 0142001619
Pellant, Chris. Rocks and Minerals. Smithsonian Handbooks. New York: Dorling Kindersley, 2002. ISBN 0789491060
Shaffer, Paul R., Herbert S. Zim, and Raymond Perlman. Rocks, Gems and Minerals. Rev. ed. New York: St. Martin's Press, 2001. ISBN 1582381321
Mineral Gallery. The Mineral Halite. Amethyst Galleries, 2006.
Spiroff, Kiril. An Unusual Occurrence of Halite. American Mineralogist. 22:931-33, 1937. Retrieved September 10, 2007.
External links
All links retrieved July 25, 2017.

Halite Mineral Data WebMineral.com.
The Mineral and Gemstone Kingdom: Halite Minerals.net.
Halite DesertUSA.

Credits
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