sylvite

Also known as sylvine, Syl

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 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. Sylvite has a salty taste with a distinct bitterness.

Key facts

Mineral.name: Sylvite
Mineral.category: Halide mineral
Mineral.image: Mineral Silvina GDFL105.jpg
Mineral.imagesize: 250px
Mineral.formula: KCl
Mineral.IMAsymbol: Syl
Mineral.molweight: 74.55 g/mol
Mineral.strunz: 3.AA.20
Mineral.system: Isometric
Mineral.class: Hexoctahedral (mm) H-M symbol: (4/m 2/m)
Mineral.symmetry: Fm3m
Mineral.unit cell: a = 6.2931 Å; Z = 4
Mineral.color: Colorless to white, pale gray, pale blue; may be yellowish red to red due to hematite inclusions
Mineral.habit: As cubes and octahedra; columnar, in crusts, coarse granular, massive
Mineral.cleavage: Perfect on [100], [010], [001]
Mineral.fracture: Uneven
Mineral.tenacity: Brittle to ductile
Mineral.mohs: 2