General Information:
Chemical Formula:
Fe++3Al2(SiO4)3
Composition:
(Molecular Weight = 497.75 gm)
Aluminum 10.84 % Al
Iron 33.66 % Fe
Silicon 16.93 % Si
Oxygen 38.57 % O
Empirical Formula:
Fe2+3Al2(SiO4)3
Environment:
Metamorphic and pegmatitic rocks.
Locality:
TL: Alabanda in Asia Minor.
Name Origin:
Named after its locality.
Physical Properties:
Cleavage:
None
Color:
brown, brownish red, red, black, or black red.
Density:
4.09 - 4.31, Average = 4.19
Diaphaniety:
Transparent to Subtransparent to translucent
Habits:
Massive - Lamellar - Distinctly foliated fine-grained forms., Granular - Generally occurs as anhedral to subhedral crystals in matrix.,
Hardness:
7-8
Luminescence:
Non-fluorescent.
Luster:
Vitreous - Resinous
Streak:
white
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