Sylvite

Sylvite
Mineral Silvina GDFL105.jpg
General
CategoryHalide mineral
Formula
(repeating unit)
KCl
Strunz classification3.AA.20
Crystal systemIsometric
Crystal classHexoctahedral (m3m)
H-M symbol: (4/m 3 2/m)
Space groupFm3m
Unit cella = 6.2931 Å; Z = 4
Identification
Formula mass74.55 g/mol
Color

Colorless to white, pale gray, pale blue; may be yellowish red

to red due to hematite inclusions
Crystal habitAs cubes and octahedra; columnar, in crusts, coarse granular, massive
CleavagePerfect on [100], [010], [001]
FractureUneven
TenacityBrittle to ductile
Mohs scale hardness2
LusterVitreous
Streakwhite
DiaphaneityTransparent to translucent
Specific gravity1.993
Optical propertiesIsotropic
Refractive index1.4903
PleochroismVisible in colored crystals
Ultraviolet fluorescenceNone
SolubilitySoluble in water
Other characteristicssalty to bitter taste
References[1][2][3]

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.[4] 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.[5] 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 only found in very dry saline areas. Its principal use is as a potassium fertilizer.

Sylvite
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, Canada were formed by the evaporation of a Devonian seaway. Sylvite is the official mineral of Saskatchewan.

Sylvite was first described in 1832 at Mt. Vesuvius near Napoli in Italy and named for the Dutch chemist, François Sylvius de le Boe (1614–1672).[1]

Sylvite, along with quartz, fluorite and halite, is used for spectroscopic prisms and lenses.[6]

Other Languages
Afrikaans: Silviet
azərbaycanca: Silvin
беларуская: Сільвін
català: Silvina
čeština: Sylvín
Deutsch: Sylvin
eesti: Sülviin
español: Silvina
Esperanto: Silvino
euskara: Silbita
فارسی: سیلویت
galego: Silvina
Հայերեն: Սիլվին
italiano: Silvite
עברית: סילביט
қазақша: Сильвин
lietuvių: Silvinas
magyar: Szilvin
Nederlands: Sylviet
日本語: カリ岩塩
norsk nynorsk: Sylvin
occitan: Silvita
português: Silvina
română: Silvină
русский: Сильвин
slovenščina: Silvin (mineral)
suomi: Sylviini
svenska: Sylvin
українська: Сильвін
Tiếng Việt: Sylvit
中文: 钾石盐