Alunogen

Alunogen also called feather alum and hair salt is a colourless to white (although often coloured by impurities) fibrous aluminium sulfate mineral often found on the walls of mines and quarries.Alunogen has the chemical formula: Al2(SO4)3·17H2O.
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(n.)
A white fibrous mineral frequently found on the walls of mines and quarries, chiefly hydrous sulphate of alumina; -- also called feather alum, and hair salt.
  

General Information:
 Chemical Formula:
Al2(SO4)3·17(H2O)
 Composition:
(Molecular Weight = 639.45 gm)
Aluminum 4.22 % Al
Hydrogen 5.67 % H 
Sulfur 15.04 % S 
Oxygen 75.06 % O 
 Empirical Formula:
Al(SO4)3·18(H2O)
 Name Origin:
From the Latin alumen ="alum" and the Greek genos ="origin."
Physical Properties:
 Cleavage:
[010] Perfect
 Color:
white, yellowish white, reddish white, or yellowish white.
 Density:
1.65 - 1.78, Average = 1.71
 Diaphaniety:
Transparent
 Habits:
Acicular - Occurs as needle-like crystals., Fibrous - Crystals made up of fibers., Encrustations - Forms crust-like aggregates on matrix.
 Hardness:
1.5-2 - Talc-Gypsum
 Luminescence:
None.
 Luster:
Vitreous - Pearly
 Streak:
white
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