The color of rock salt—A review

Lattice deformation of blue halite from Zechstein evaporite basin: Kłodawa Salt Mine, Central Poland

“…The presence of epigenetic sediments does not always guarantee the occurrence of blue halite, though the co-occurrence of blue halite with the primary potassium-magnesium salts, such as carnallite and polyhalite, was rarely observed. Additionally, the blue halite associations together with the epigenetic sediments were related to tectonites (Sonnenfeld 1995;Davidge and Pratt 1963). The tectonic deformation of the salt strata observed in macroscopic scale has been manifested in microscopic scale as a specific birefringence in thin samples not only of blue halite but also of natural colourless halite from the Kłodawa Salt Mine.…”

“…For example, there are several papers describing radiation damage of halite mainly for the usage of exploited salt mines as waste storages (Groote et al 1991a(Groote et al ,b, 1994Seinen et al 1992Seinen et al , 1994aWeerkamp et al 1994;den Hartog 1999;den Hartog and Vainshtein 1997;den Hartog et al 2002den Hartog et al , 2007. A review article by Sonnenfeld (1995) summarised the state of the art of the colour of rock salt. He pointed out factors responsible for the blue colour of halite crystals such as irradiation, soaking in sodium vapours, introducing impurities, inclusions of interstitial matter or structural defects in the crystal lattice.…”

“…He pointed out factors responsible for the blue colour of halite crystals such as irradiation, soaking in sodium vapours, introducing impurities, inclusions of interstitial matter or structural defects in the crystal lattice. Blue halite occurs frequently in tectonically disturbed zones (tectonites) accompanied by sylvite veins (Davidge and Pratt 1963;Sonnenfeld 1995) and is considered as mineralogical rarity. Especially important for understanding the blue colouration of the halite from Kłodawa Salt Mine seems to be the report on blue halite by Howard and Kerr (1960).…”

The Huarhua Rock Salt Mine: Archaeological Implications of Modern Extraction Practices

“…The rock salt comes in a variety of colors and textures. Different inclusions, impurities, and structural defects in the salt's crystal lattice cause the various shades of black, red, pink, and white (e.g., Sonnenfeld 1995 ) . Ground water seeping through the mine alters the salt's texture and the salt is often layered in alternating bands of color ranging from 0.5 cm to 0.75 m in thickness.…”

Salt disposal of heat-generating nuclear waste.

“…Farbe centers (F centers) are often associated with radiation damage that creates blue and black salt crystals by virtue of a stoichiometric excess of sodium. Sonnenfeld (1995) explains the several possible causes for colored salt, but no physical or mechanical behavior of importance to repository performance is attributed to radiation effects on salt.…”