bischofite

Bischofite is the mineral form of magnesium chloride hexahydrate, with the chemical formula MgCl2·6H2O. It occurs as colorless to white crystals in evaporite deposits formed by the evaporation of magnesium-rich saline waters and is commonly associated with other evaporite minerals such as halite and carnallite. The mineral forms through progressive evaporation in arid environments and can be encountered in saltworks where brines have concentrated.

The mineral is soluble in water and tends to deliquesce in moist air, so handling and storage are usually done under dry conditions. Bischofite is recovered from natural brine deposits or mined as a crystalline form and serves as a natural source of magnesium chloride.

In industrial contexts, magnesium chloride derived from brines is used for chemical synthesis, as a de-icing agent for roads, and for dust control. It also finds applications in certain pharmaceutical and cosmetic formulations. Although bischofite itself is a natural mineral, most industrial magnesium chloride is produced from brines or salts derived from brines rather than from raw mineral crystallization.

Specimens of bischofite are collected by mineral enthusiasts for their delicate hydrated halide crystals and for their role in illustrating evaporite formation processes. The mineral contributes to the broader understanding of how magnesium-bearing brines concentrate and crystallize in saline environments.