Sylvite is an evaporite mineral of composition KCl. It is a member of the halide group and is a relatively common mineral in saline environments. It is in the isometric crystal class and has the halite structure. Crystals are often orange in color.
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 principle use is as a potassium fertilizer. 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.
Importance in Soil Environments
Due to its high solubility sylvite is not an important mineral in most soils maintained under natural conditions; however, its use as a fertilizer is of great importance, but it does not persist for any substantial period of time in humid region soils.
Swanson, Tatge (1960)JC Fel. Reports, NBS