Sylvite, or sylvine, is

potassium chloride Potassium chloride (KCl, or potassium salt) is a metal halide salt composed of potassium and chlorine. It is odorless and has a white or colorless vitreous crystal appearance. The solid dissolves readily in water, and its solutions have a sa ...

(KCl) in natural

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...

form. It forms crystals in the

isometric The term ''isometric'' comes from the Greek for "having equal measurement". isometric may mean: * Cubic crystal system, also called isometric crystal system * Isometre, a rhythmic technique in music. * "Isometric (Intro)", a song by Madeon from ...

system very similar to normal rock salt,

halite Halite ( ), commonly known as rock salt, is a type of salt, the mineral (natural) form of sodium chloride ( Na Cl). Halite forms isometric crystals. The mineral is typically colorless or white, but may also be light blue, dark blue, purple, pi ...

( NaCl). The two are, in fact,

isomorphous In mathematics, an isomorphism is a structure-preserving mapping or morphism between two structures of the same type that can be reversed by an inverse mapping. Two mathematical structures are isomorphic if an isomorphism exists between them. ...

. Sylvite is colorless to white with shades of yellow and red due to inclusions. It has a

Mohs hardness The Mohs scale ( ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fair ...

of 2.5 and a

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

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 An evaporite () is a water- soluble sedimentary mineral deposit that results from concentration and crystallization by evaporation from an aqueous solution. There are two types of evaporite deposits: marine, which can also be described as oce ...

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. 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 Saskatchewan is a Provinces and territories of Canada, province in Western Canada. It is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and to the south by the ...

, Canada. The vast deposits in Saskatchewan were formed by the evaporation of a

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

seaway. Sylvite is the official mineral of Saskatchewan. Sylvite was first described in 1832 at

Mount Vesuvius Mount Vesuvius ( ) is a Somma volcano, somma–stratovolcano located on the Gulf of Naples in Campania, Italy, about east of Naples and a short distance from the shore. It is one of several volcanoes forming the Campanian volcanic arc. Vesuv ...

near

Napoli Naples ( ; ; ) is the regional capital of Campania and the third-largest city of Italy, after Rome and Milan, with a population of 908,082 within the city's administrative limits as of 2025, while its province-level municipality is the thir ...

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

and named after historical KCl designations ''sal degistivum Sylvii'' and ''sal febrifugum Sylvii'', which are named after the

Dutch Dutch or Nederlands commonly refers to: * Something of, from, or related to the Netherlands ** Dutch people as an ethnic group () ** Dutch nationality law, history and regulations of Dutch citizenship () ** Dutch language () * In specific terms, i ...

physician and chemist François Sylvius de le Boe (1614–1672). Sylvite, along with quartz,

fluorite Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs scal ...

and halite, is used for

spectroscopic Spectroscopy is the field of study that measures and interprets electromagnetic spectra. In narrower contexts, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. Spectrosc ...

prisms and lenses.

References

External links

Mineral Resources of Saskatchewan
{{commons category, Sylvite Potassium minerals Chloride minerals Cubic minerals Minerals in space group 225 Evaporite Potash Rocksalt group

See also

References

External links