This rock is essentially composed of halite, often with impurities of clay minerals and iron oxides. The rock is colored reddish brown when iron oxides are present.

TEXTURE Rock salt is usually massive and coarsely crystalline, sometimes occurring as distinct cubic crystals. Under pressure, the rock salt may flow, forming salt plugs that intrude other strata.

ORIGIN Forms from saline waters, such as salt lakes, in a sequence that includes other evaporite minerals, such as dolomite and gypsum.

Grain size: Coarse

Classification: Chemical

Fossils: None

Grain shape: –