Formula: NaCl
Chloride, halite group
Crystal System: Isometric
Specific gravity: 2.168 measured, 2.165 calculated
Hardness: 2
Streak: White
Colour: Pure halite is colourless or white; it can also be reddish, yellow, grey or blue. The blue colour arises when halite sodium ions are changed to colloidal sodium metal by the action of natural radiation (https://www.youtube.com/watch?v=ejucgGmeJMA).
Solubility: Readily soluble in water
Melts at 804°C
Common impurities: I,Br,Fe,O

Evaporite Deposits
Fumeroles and hot spring deposits

Halite is dissolved in the waters of salt springs, salt lakes and the ocean. It is a common mineral, occurring often in extensive beds and irregular masses, precipated by evaporation with gypsum, sylvite, anhydrite and calcite. It is a major salt in playa deposits of enclosed basins. It occurs as halite deposits in steppes and deserts, and in fumeroles.

At the Mallee District, Murray Basin, south-eastern Australia, halite is precipitated in many of the evaporite basins (AJM 10.1.20).

At Lake Crosbie, Victoria, Australia, halite occurs associated with glauberite and gypsum in black mud under a salt crust which covers the lake (AJM 10.1.17-18).

At the Francon Quarry, Montreal, Quebec, Canada, halite has been found as a rare occurrence admixed with nahcolite (Minrec 37.1.36).

At the Solno mine, Inowrocław, Kuyavian-Pomeranian Voivodeship, Poland, pure gypsum was found at the depth of over 13 m, brine at a depth of 111.5 m and halite from about 120 m on down. In some cases post-mining halite is associated with gypsum (https://www.spiriferminerals.com/183,Halites-from-the-Solno-Salt-Mine--Poland.html).

The Winsford Rock Salt Mine, Winsford, Cheshire, England, UK, is the only salt mine in the UK, and the only mineral found there is halite, in vast deposits (RES pps 43-48).

At Sheethedges Wood Quarry, Leicestershire, England, UK, clay pseudomorphs after halite have been found (RES p 191), some associated with palygorskite (JRS 14.59).

In Nottinghamshire, England, UK, pseudomorphs of gypsum after halite have been found at the Cliffs, Radcliffe on Trent, and also at Gunthorpe Weir, East Bridgford (RES pps 245, 248).

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