Sylvite
Potassium chloride mineral
title: "Sylvite" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["potassium-minerals", "chloride-minerals", "cubic-minerals", "minerals-in-space-group-225", "evaporite", "potash", "rocksalt-group"] description: "Potassium chloride mineral" topic_path: "general/potassium-minerals" source: "https://en.wikipedia.org/wiki/Sylvite" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Potassium chloride mineral ::
::data[format=table title="Infobox mineral"]
| Field | Value |
|---|---|
| name | Sylvite |
| category | Halide mineral |
| image | Mineral Silvina GDFL105.jpg |
| imagesize | 250px |
| formula | KCl |
| IMAsymbol | Syl |
| molweight | 74.55 g/mol |
| strunz | 3.AA.20 |
| system | Isometric |
| class | Hexoctahedral (mm) |
| H-M symbol: (4/m 2/m) | |
| symmetry | Fm3m |
| unit cell | a = 6.2931 Å; Z = 4 |
| color | Colorless to white, pale gray, pale blue; may be yellowish red |
| habit | As cubes and octahedra; columnar, in crusts, coarse granular, massive |
| cleavage | Perfect on [100], [010], [001] |
| fracture | Uneven |
| tenacity | Brittle to ductile |
| mohs | 2 |
| luster | Vitreous |
| refractive | 1.4903 |
| opticalprop | Isotropic |
| pleochroism | Visible in colored crystals |
| fluorescence | None |
| streak | White |
| gravity | 1.993 |
| solubility | Soluble in water |
| diaphaneity | Transparent to translucent |
| other | Salty to bitter taste |
| references | |
| :: |
| name = Sylvite | category = Halide mineral | boxwidth = | boxbgcolor = | image = Mineral Silvina GDFL105.jpg | imagesize = 250px | caption = | formula = KCl | IMAsymbol = Syl | molweight = 74.55 g/mol | strunz = 3.AA.20 | system = Isometric | class = Hexoctahedral (mm) H-M symbol: (4/m 2/m) | symmetry = Fm3m | unit cell = a = 6.2931 Å; Z = 4 | color = Colorless to white, pale gray, pale blue; may be yellowish red to red due to hematite inclusions | habit = As cubes and octahedra; columnar, in crusts, coarse granular, massive | twinning = | cleavage = Perfect on [100], [010], [001] | fracture = Uneven | tenacity = Brittle to ductile | mohs = 2 | luster = Vitreous | polish = | refractive = 1.4903 | opticalprop = Isotropic | birefringence = | dispersion = | pleochroism = Visible in colored crystals | fluorescence= None | absorption = | streak = White | gravity = 1.993 | density = | melt = | fusibility = | diagnostic = | solubility = Soluble in water | diaphaneity = Transparent to translucent | other = Salty to bitter taste | references =
Sylvite, or sylvine, is potassium chloride (KCl) in natural mineral form. It forms crystals in the isometric system very similar to normal rock salt, halite (NaCl). The two are, in fact, isomorphous. Sylvite is colorless to white with shades of yellow and red due to inclusions. It has a Mohs hardness of 2.5 and a specific gravity of 1.99. It has a refractive index of 1.4903. Sylvite has a salty taste with a distinct bitterness.
Sylvite is one of the last evaporite minerals to precipitate out of solution. As such, it is found only in very dry saline areas. Its principal use is as a potassium fertilizer. ::figure[src="https://upload.wikimedia.org/wikipedia/commons/8/80/Mineral_Silvina_GDFL123.jpg" caption="Sylvite"] ::
::figure[src="https://upload.wikimedia.org/wikipedia/commons/a/a2/Sylvin_(aka).jpg" caption="Sylvite from [[Germany"] ::
Sylvite is found in many evaporite deposits worldwide. Massive bedded deposits occur in New Mexico and western Texas, and in Utah in the US, but the largest world source is in Saskatchewan, Canada. The vast deposits in Saskatchewan were formed by the evaporation of a Devonian seaway. Sylvite is the official mineral of Saskatchewan.
Sylvite was first described in 1832 at Mount Vesuvius near Napoli in Italy and named after historical KCl designations sal degistivum Sylvii and sal febrifugum Sylvii, which are named after the Dutch physician and chemist François Sylvius de le Boe (1614–1672).
Sylvite, along with quartz, fluorite and halite, is used for spectroscopic prisms and lenses.
References
References
- Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
- [http://www.mindat.org/show.php?id=3850&ld=1&pho= Sylvite: Sylvite mineral information and data]
- [http://webmineral.com/data/Sylvite.shtml Sylvite Mineral Data]
- [http://rruff.geo.arizona.edu/doclib/hom/sylvite.pdf Handbook of Mineralogy]
- Klein, Cornelis and Cornelius S. Hurlbut, Jr. 1993. ''Manual of Mineralogy after [[James Dwight Dana. J.D. Dana]], 21st edition''. New York: John Wiley & Sons, Inc.
- Deer, W.A., R.A. Howie, and J. Zussman. 1992. ''An Introduction to the Rock-Forming Minerals'' 2nd ed. New York: Prentice Hall.
- Watts, Henry. (1883). "A Dictionary of Chemistry and the Allied Branches of Other Sciences". Longmans, Green, and Company.
- Motz, Lloyd. "Spectroscopy". Microsoft Encarta 2009.
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