Aluminite

Aluminite is a hydrous aluminium sulfate mineral with formula: Al2SO4(OH)4·7(H2O). It is an earthy white to gray-white monoclinic mineral which almost never exhibits crystal form. It forms botryoidal to mammillary clay-like masses. It is very soft Mohs hardness of 1 with a specific gravity of 1.66—1.7. It forms as an oxidation product of pyrite and marcasite along with aluminous silicates and clays.
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n. aluminite

General Information:
 Chemical Formula:
Al2(SO4)(OH)4·7(H2O)
 Composition:
(Molecular Weight = 230.13 gm)
Aluminum 11.72 % Al
Hydrogen 4.82 % H 
Sulfur 13.93 % S 
Oxygen 69.52 % O 
 Empirical Formula:
Al(SO4)(OH)·5(H2O)
 Name Origin:
Named after its chemical composition.
Physical Properties:
 Cleavage:
None
 Color:
white or grayish white.
 Density:
1.66 - 1.7, Average = 1.68
 Diaphaniety:
Opaque
 Habits:
Mammillary - Larger "breast-like" rounded forms resembling botryoidal (e.g. malachite)., Botryoidal - "Grape-like" rounded forms (e.g.. malachite)., Earthy - Dull, clay-like texture w ith no visible crystalline affinities, (
 Hardness:
1 - Talc
 Luminescence:
Fluorescent.
 Luster:
Earthy (Dull)
 Streak:
white
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