Sylvite is the mineral in which KCl or potassium chloride exists in nature. The shape of its crystals formed isometrically, is analogous to halite, common rock salt (NaCl.) In fact, these two are isomorphic. The color of sylvite is white to colorless with a tinge of red or yellow on account of inclusions. It displays a distinctly bitter and salty taste. Sylvite is among the last evaporating minerals that get precipitated out of solutions. It occurs in extremely dry and saline areas and is mainly used as potassium manure.
Derivation of Name
Sylvite was initially explained in at Mt. Vesuvius in 1832, near Napoli, Italy and it was named after François Sylvius de le Boe, a Dutch chemist, who lived from 1614 to 1672.
This mineral, containing potassium chloride, is the main source of potassium. It is not found as frequently as halite (meaning) sodium chloride. It occurs as bitter-tasting, soft, and white to grayish, glassy masses with gypsum and halite.
Occasionally, it is used as gemstones.
Sylvite occurs in several evaporite deposits throughout the world. Huge deposits are found in Utah, western Texas in the United States, plus New Mexico, though its worldwide largest source is located in Saskatchewan in Canada. The immense deposits in Canada were created by a Devonian time seaway’s evaporation. Saskatchewan has Sylvite as its official mineral.
Sylvite or sylvine is a key source of potash or potassium and is used in making fertilizers. Because of the tremendous demands of potassium, sylvite deposits have become extremely valuable. It is not much of a collectors’ item. Its well formed crystals are frequently reddish due to the presence of hematite as inclusions. It dissolves in water very easily, making it imperative to keep its containers tightly closed at moisture present in the air can affect its appearance. You should never use water for cleaning sylvite specimen.
White to colorless, pale gray or blue; can be red to yellowish red due hematite inclusions.