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. [5] 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.

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.

From Latin "sal digestibus Sylvii", salts of Sylvius, named after Franz (Franciscus) Sylvius de le Boë (15 March 1614, Hanau, Holy Roman Empire - 19 November 1672, Leiden, Republic of the United Netherlands), a physician and chemist of Leiden, Netherlands.

Sylvite is defined as a mineral that can be distinguished from halite by its significantly lower refractive index, despite having a similar crystal morphology. AI generated definition based on: Interpretation of Micromorphological Features of Soils and Regoliths (Second Edition) , 2018

sylvite, halide mineral, potassium chloride (KCl), the chief source of potassium. It is rarer than halite (sodium chloride) and occurs as soft, bitter-tasting, white or grayish, glassy cubes or as masses with halite and gypsum in evaporite deposits in the vicinity of Stassfurt, Ger., and in southwestern New Mexico , U.S.

Sylvite KCl c 2001-2005 Mineral Data Publishing, version 1 Crystal Data: Cubic. Point Group: 4/m32/m. As cubes, cubo-octahedra, and octahedra, to 15 cm; may be columnar, in crusts, coarse granular to compact, massive. Physical Properties: Cleavage: {001}, perfect. Fracture: Uneven. Tenacity: Brittle, ductile under low strain.

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.

Sylvite. Comments: Translucent sylvite crystal cluster, somewhat deliquescent. Location: F.O. Kailwerk, Sigmundshall, near Wunstorf, Niedersachsen, Germany. Scale: See Photo. © Jeff Weissman / Photographic Guide to Mineral Species

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.

Sylvite, also called sylvine, is a major source of potassium or potash used in fertilizer products. So great is the need for potassium that sylvite deposits are considered very valuable economically. As a mineral specimen sylvite does not get much attention.