Hanksite
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.
| Hanksite | |
|---|---|
Hanksite crystal from Searles Lake | |
| General | |
| Category | Sulfate minerals, sulfate carbonate |
| Formula (repeating unit) | Na22K(SO4)9(CO3)2Cl |
| IMA symbol | Hks |
| 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 | |
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