Halite
Halite, also known as stone salt, is a very common mineral but rarely available as a gem that is faceted. It is soluble in water and so hard to facet. Halite can be found in many localities worldwide including evaporative that is current such as near Salt Lake City, Utah and Searles Lake, California, United States. In these locations, it crystallizes out of evaporating brine lakes. It is also found in ancient bedrock throughout the globe where large salt that is extinct and seas evaporated millions of years ago leaving dense deposits of sodium. The cities of Cleveland and Detroit sit above huge Halite deposits. These deposits which are undergrond often mined for use as road salt.
Halite often types as perfect cubes but also types some unusual and practices that are interesting. One of the interesting that is most is named a “hopper” or “skeletal” crystal where just the sides of the crystal grow outward from the center making hollow, stairstep faces recessed toward the biggest market of the crystal. Halite crystals are occasionally colored an attractive pastel pink by inclusions of bacterial debris being caught during crystallization in a lake that is evaporative. Halite crystals from Saxony-Anhalt and Lower Saxony, Germany have now been discovered with amazing color that is azure-blue that is caused by the clear presence of Chloride gas.
Halite occurs worldwide. Well-studied deposits consist of: around Hallstadt, Salzburg, and Hall, near Innsbruck, Tirol, Austria. From Bex, Vaud, Switzerland. In Germany, from Stassfurt-Leopoldshall, 34 south that is km of, Saxony-Anhalt. Deposits with large crystals at Wieliczka (Galicia) and Bochnia, Poland. At Girgenti and Racalmuto, Sicily, Italy. Into the Salt Number, Punjab, India. In the USA, in the Michigan Basin, underlying Ohio, Michigan, and New York; as numerous salt domes across the Gulf Coast; plus in the Permian Basin of Texas and brand new Mexico; large crystals at the Potash Corporation of America mine, Carlsbad potash district, Eddy County, New Mexico.
| Category: | Halide mineral | ||||||||||||||||||||
| Chemical Formula: | NaCl | ||||||||||||||||||||
| Sodium Chloride | |||||||||||||||||||||
| Molecular Weight: | 58.44 gm | ||||||||||||||||||||
| Composition: |
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| Crystallography: | Isometric – Hexoctahedral |
| Crystal Habit: | Crystals normally cubic, to 1 m, rarely octahedral, elongated along [100] or [111]. Crystal faces often cavernous and stepped (hopper crystals). Massive. Coarsely granular to compact; columnar, stalactitic or capillary forms rare. |
| Twinning: | None |
| Cleavage: | [100] Perfect, [010] Perfect, [001] Perfect |
| Fracture: | Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 2.0 – 2.5 |
| Density: | 2.168 (g/cm3) |
| Luminescence: | Rarely fluorescent; SW UV = red, green (organic inclusions), orange, LW UV = red, green orange. |
| Radioactivity: | Not Radioactive |
| Other: | Soluble in H2O. Saline taste. Caution: Licking or ingesting raw halite in the “wild” could cause health problems due to unidentified admixed substances (such as alkaline compounds). |
| Color: | Colorless or White when pure, Gray, Yellow, Orange, light to dark Blue, Purple, Pink to Red; Colorless to faintly tinted in thin section. |
| Transparency: | Transparent to Translucent |
| Luster: | Vitreous |
| Refractive Index: | 1.5443 Isotropic |
| Birefringence: | 0.000 (Isotropic) |
| Dispersion: | Moderately Strong |
| Pleochroism: | Weak; The pleochroism is sometimes developed in colored material after being subjected to pressure. |
