General Information:
Chemical Formula:
[ ]Fe++7Si8O22(OH)2
Composition:
(Molecular Weight = 1,001.61 gm)
Iron 39.03 % Fe
Silicon 22.43 % Si
Hydrogen 0.20 % H
Oxygen 38.34 % O
Empirical Formula:
Fe2+7(Si8O22)(OH)2
IMA Status:
Approved IMA 1978
Physical Properties:
Cleavage:
[110] Perfect, [???] Distinct
Color:
ashen, brown, brownish green, or dark gray.
Density:
3.4 - 3.5, Average = 3.45
Diaphaniety:
Translucent to opaque
Habits:
Fibrous - Crystals made up of fibers., Columnar - Forms columns, Massive - Uniformly indistinguishable crystals forming large masses.
Hardness:
5-6 - Between Apatite and Orthoclase
Luminescence:
Non-fluorescent.
Luster:
Vitreous - Pearly
Streak:
colorless
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