Hydrohalite - Hydrohalite is a very rare mineral mistaken for being a variety of Halite. It is a separate mineral and has a formula of "NaCl · 2H₂O", which is in essence Halite containing water. It forms only under very unique conditions where the water does not dissolve the salt. When the salt in sea water or saline spring water in very cold climates crystallizes, it forms together with ice which has no dissolving effect on salt. The ice forms an integral part of the structure of the mineral, and causes the mineral to be stable.