1.3" Double-Terminated Hanksite Crystal - Trona, California

Hanksite is a sulphate mineral with the chemical formula Na22K(SO4)9(CO3)2Cl. It is unique as a sulphate since it contains both sulphate and carbonate ion groups, one of only a few of its kind. It forms in evaporate deposits as a product of the evaporation of water from Lake Searles in Trona, California. Once water evaporates from this lake bed and shores, the remaining concentrated minerals form crystals. Typically halite is the first crystal to form, but in more unusual cases, borax, sulphohalite, and hanksite can form when the mineral concentration is exceptional.