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 sulphate class mineral as there are more of these groups than the carbonate.
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General Information:
 Chemical Formula:
KNa22(SO4)9(CO3)2Cl
 Composition:
(Molecular Weight = 1,564.92 gm)
Potassium 2.50 % K 
Sodium 32.32 % Na
Carbon 1.54 % C 
Sulfur 18.44 % S 
Chlorine 2.27 % Cl
Oxygen 42.94 % O 
 Empirical Formula:
KNa22(SO4)9(CO3)2Cl
 Environment:
Continental evaporite deposits.
 Locality:
Searles Lake, San Bernardino Co. California.
Physical Properties:
 Cleavage:
[0001] Good
 Color:
colorless, gray, grayish black, yellow, or yellowish white.
 Density:
2.5
 Diaphaniety:
Transparent
 Habits:
Crystalline - Coarse - Occurs as well-formed coarse sized crystals., ,
 Hardness:
3 - Calcite
 Luminescence:
Non-fluorescent.
 Luster:
Vitreous - Greasy
 Streak:
white
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