Rock Salt (primarily Halite)
Image: Hubertl (CC BY-SA 4.0)
Mineral NameRock Salt (primarily Halite)
Chemical FormulaNaCl
Mohs Hardness2
Crystal Systemcubic
Lustervitreous
Streak Colorwhite
Cleavageperfect cubic (three directions at 90 degrees)
Fractureconchoidal to uneven
Specific Gravity2.16
Colorspink, orange, reddish-brown, white
Transparencytranslucent to opaque
Type LocalityKhewra Salt Mine, northern Pakistan
Mineral GroupHalides
Usesculinary, industrial, decorative, bath salts
Associated Mineralspolyhalite, iron oxides, gypsum, anhydrite
Raritycommon
Description
Several large, rough pieces of reddish-pink to orange rock salt are displayed alongside smaller crushed grains and a jar of finer salt. The pieces show a crystalline texture and varying shades of color.
Geological Context
Rock salt forms from the evaporation of ancient saline seas or lakes, leading to the precipitation and accumulation of halite and other evaporite minerals in thick sedimentary beds. The Khewra Salt Mine deposit is part of a large evaporite sequence.
