Zirklerite

General Information:
 Chemical Formula:
(Fe++,Mg)9Al4Cl18(OH)12·14(H2O) (?)
 Composition:
(Molecular Weight = 1,634.03 gm)
Magnesium 3.35 % Mg
Aluminum 6.60 % Al
Iron 23.07 % Fe
Hydrogen 2.47 % H 
Chlorine 39.05 % Cl
Oxygen 25.46 % O 
 Empirical Formula:
9(Fe2+0.75)9(Mg0.25)Al4Cl18(OH)12·14(H2O)
 Environment:
Marine evaporite deposits.
 Locality:
Hope, Hanover, Germany.
 Name Origin:
Named after Zirkler, director of the Aschersleben potash works, Germany.
Physical Properties:
 Cleavage:
[1011] Perfect, [1011] Perfect, [1011] Perfect
 Color:
white or light gray.
 Density:
2.6
 Diaphaniety:
Transparent to translucent
 Habits:
Massive - Uniformly indistinguishable crystals forming large masses., ,
 Hardness:
3.5 - Copper Penny
 Luster:
Vitreous - Dull
 Streak:
white
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