General Information:
Chemical Formula:
Al2Si2O5(OH)4
Composition:
(Molecular Weight = 258.16 gm)
Aluminum 20.90 % Al
Silicon 21.76 % Si
Hydrogen 1.56 % H
Oxygen 55.78 % O
Empirical Formula:
Al2Si2O5(OH)4
Name Origin:
Named after O. d'Halloy (1707-1789).
Physical Properties:
Cleavage:
None
Color:
white, yellowish white, reddish white, brownish white, or greenish white.
Density:
2 - 2.6, Average = 2.29
Diaphaniety:
Translucent to opaque
Habits:
Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite)., ,
Hardness:
2 - Gypsum
Luminescence:
None.
Luster:
Earthy (Dull)
Streak:
white
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