Hanksite
Hanksite is a mineral, distinguished as one of only a handful that contain both carbonate and sulfate ion groups. This can bring confusion as to which category to place it into, normally it is regarded as sulfate class mineral as there are more of these groups than the carbonate.
Occurrence
Hanksite is normally found in crystal form as evaporite deposits. Hanksite crystals are large but not complex in structure. It is often found in Searles Lake, San Bernardino County and Mono Lake, California.
Chemistry
Composition: Na22K(SO4)9(CO3)2Cl, Sodium, Potassium, Sulfate, Carbonate, Chloride
Physical characteristics
Hanksite can be colorless, white, gray, green or yellow and is transparent or translucent. The mineral's hardness is approximately 3 to 3.5 The specific gravity is approximately 2.5 (slightly below average). The mineral is salty to the taste, can be covered in a light film of dust and sometimes glows pale yellow in ultra-violet light. Typical growth habits are hexagonal prisms or tabular with pyramidal terminations. The streak of Hanksite is white. Can contain inclusions of clay that the crystal formed around while developing.