Iron Oxy Hydroxide Alfa type
α-FeO(OH)
Chemical name
Iron Oxy Hydroxide Alfa type |
Mineral name
Goethite |
Chemical formula
α-FeO(OH) |
Crystal system
orhorhombic |
Crystal Class
orthorhombic-dipyramidal (2/m 2/m 2/m) |
Space Group
Pbnm |
Unit cell
a [Å]:4.65 b [Å]:10.02 c [Å]:3.04 |
Molecular weight [g/mol]
88.85 |
Formula units
Z=4 |
Mohs hardness
5 - 5.5 |
Density [g/cm3]
3.3 - 3.4 |
Cleavage
perfect on {010} |
Fracture / Tenacity
uneven to splintery |
Color
Vivid, dark orange, opaque crystals |
Refractive Index
Opaque to sub-translucen |
Solubility in water
insoluble at pH 7 |