General Information:
Chemical Formula:
Fe+++O(OH)
Composition:
(Molecular Weight = 88.85 gm)
Iron 62.85 % Fe
Hydrogen 1.13 % H
Oxygen 36.01 % O
Empirical Formula:
Fe3+O(OH)
Environment:
Common in iron ore deposits.
Locality:
Mesabi district, Minnesota, USA.
Name Origin:
Named after the German poet, J. W. Goethe (1749-1832).
Physical Properties:
Cleavage:
[010] Perfect, [100] Distinct
Color:
brown, reddish brown, yellowish brown, brownish yellow, or ocher yellow.
Density:
3.3 - 4.3, Average = 3.8
Diaphaniety:
Subtranslucent to opaque
Habits:
Acicular - Occurs as needle-like crystals., Reniform - "Kidney like" in shape (e.g.. hematite)., Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite )
Hardness:
5-5.5 - Apatite-Knife Blade
Luminescence:
None.
Luster:
Adamantine - Silky
Streak:
yellowish brown
More details...