Halite (Rock Salt)

Physical Properties

Hardness: 2-2.5 on Mohs scale; Color: Colorless to white (can be blue or pink with impurities); Luster: Vitreous (glassy); Crystal Structure: Cubic/Isometric; Cleavage: Perfect cubic; Specific Gravity: 2.16.

Formation & Geological History

Formed through the evaporation of saline water in sedimentary basins, such as salt lakes or enclosed seas. These evaporite deposits can date from the Precambrian to the present day.

Uses & Applications

Primary source of common table salt, used for road de-icing, chemical production (chlorine and sodium hydroxide), food preservation, and as decorative lamps or collector specimens.

Geological Facts

Halite is the mineral form of sodium chloride. It can form 'hopper crystals' where the edges grow faster than the faces, creating a step-like cavernous shape. It is highly soluble in water and will eventually dissolve if exposed to moisture.

Field Identification & Locations

Identify in the field by its perfect 90-degree cubic cleavage, salty taste (though not recommended for unknown minerals), and low hardness. Commonly found in locations like the Dead Sea, Wieliczka Salt Mine, and Searles Lake, California.

Identified on: 4/21/2026

Mode: Standard