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The Mineral sylvite

Octahedral Sylvite Crystals

Sylvite is an economically important mineral and is extensively mined, though it is rarely represented in mineral collections as attractive specimens. It is the most significant form of potash, or potassium-bearing compounds, and has many industrial uses.

Sylvite is very similar to Halite, and is ismorphous with it, but it has a more bitter taste an greater solubility. It sometimes forms as a contrasting accessory mineral to deeply colored Halite specimens. Sylvite is named after named after François Sylvius de le Boe (1614-1672), a Dutch chemist and physician.

Chemical Formula

KCl

Color

Colorless, white, light yellow. Often red or orange from Hematite inclusions.

Crystal System

Isometric

Properties

Streak
White

Hardness
2 - 2.5

Transparency
Transparent to translucent

Specific Gravity
2.0

Luster
Vitreous

Cleavage
1,all sides

Fracture
Conchoidal

Tenacity
Brittle

Other ID Marks
1) Strong, bitter taste.
2) Highly soluble in water, especially warm water.

Crystal Habits

Octahedral and cubic with modified octahedral faces. Less commonly cubic. Also in groups of octahedral or cubic crystals, grainy, massive, compact, and fibrous.

Additional Information

Composition
Potassium chloride

In Group
Halides

Striking Features
Bitter taste and low hardness

Environment
Evaporite deposits such as dry lakes and saline lake shorelines, sedimentary salt beds, and volcanic fumaroles.

Rock Type
Igneous, Sedimentary

Other Names

Sylvine

Varieties

Sylvinite

- A mixture of Sylvite and Halite.

Uses

Sylvite is the main source of potash, which is an important ingredient in fertilizers. It has other important industrial uses, including aluminium recycling, metal electroplating, and in oil drilling fluids. It is the chief ingredient of potassium supplements, which are used to treat or prevent low potassium conditions such as hypokalemia.

Noteworthy Localities

Sylvite was first discovered in very small crystals in the volcanic fumaroles of Mt. Vesuvius, Naples Province, Italy. Other important European localities include Muntanya de Sal (Salt Mountain), Cardona, Catalonia, Spain; and the Boulby Mine, Loftus, Yorkshive, England. In Germany, good Sylvite has been found at Wathlingen, Lower Saxony; Stassfurt, Saxony-Anhalt; and at the Hattorf Potash Works, Werra valley, Hesse.

In the U.S., the two most important deposits of Sylvite are the Carlsbad Potash District, Eddy Co., New Mexico; and Niland, near the Salton Sea, Imperial Co., California. Some of the world's largest deposits of Sylvite are in Canada in the province of Saskatchewan, especially at Esterhazy and Rocanville.