Hanksite | |
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![]() Hanksite crystal from Searles Lake | |
General | |
Category | Sulfate minerals, sulfate carbonate |
Formula (repeating unit) | Na22K(SO4)9(CO3)2Cl |
IMA symbol | Hks[1] |
Strunz classification | 7.BD.30 |
Crystal system | Hexagonal |
Crystal class | Dipyramidal (6/m) H–M symbol: (6/m) |
Space group | P63/m |
Unit cell | a = 10.465(21) Å c = 21.191(43) Å; Z = 2 |
Identification | |
Color | Colorless to pale yellow, may be grayish green due to clay inclusions |
Crystal habit | Occurs as short prismatic to tabular hexagonal crystals |
Cleavage | Good on {0001} |
Fracture | Uneven |
Tenacity | Brittle |
Mohs scale hardness | 3–3.5 |
Luster | Vitreous to dull |
Streak | White |
Diaphaneity | Transparent to translucent |
Specific gravity | 2.562 |
Optical properties | Uniaxial (−) |
Refractive index | nω = 1.481, nε = 1.461 |
Birefringence | δ = 0.020 |
Ultraviolet fluorescence | Pale yellow under LW UV |
Solubility | Readily soluble in water |
References | [2][3][4] |
Hanksite is a sulfate mineral, distinguished as one of only a handful that contain both carbonate and sulfate ions (a sulfate carbonate). It has the chemical formula Na22K(SO4)9(CO3)2Cl.