General Information:
Chemical Formula:
Fe++Al2O4
Composition:
(Molecular Weight = 173.81 gm)
Aluminum 31.05 % Al
Iron 32.13 % Fe
Oxygen 36.82 % O
Empirical Formula:
Fe2+Al2O4
Environment:
Magmatic.
Locality:
Pobezovice, Czechoslovakia.
Name Origin:
From the old Latin, Hercynia Silva, "Forested Mountains."
Physical Properties:
Cleavage:
[111] Indistinct, [111] Indistinct, [111] Indistinct
Color:
black.
Density:
3.95
Diaphaniety:
Opaque
Habits:
Euhedral Crystals - Occurs as well-formed crystals showing good external form., Massive - Granular - Common texture observed in granite and other igneous rock., Granular - Generally o ccurs as anhedral to subhedral crystals
Hardness:
7.5 - Garnet
Luminescence:
None.
Luster:
Vitreous (Glassy)
Streak:
dark green
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