Gamma Iron Oxy Hydroxide
Υ-Fe(3+)O(OH)
Chemical name
Gamma Iron Oxy Hydroxide
Mineral name
Lepidocrodite
Chemical formula
Υ-Fe(3+)O(OH)
Crystal system
orthorhombic
Crystal Class
orthorhombic-dipyramidal (2/m 2/m 2/m)
Space Group
Cmc2_1
Unit cell
a [Å]:3.88
b [Å]:12.54
c [Å]:3.07
Formula units
Z=4
Frequent crystal surfaces
{010}
Mohs hardness
5
Density [g/cm3]
4.0
Cleavage
perfect on (010)
Fracture / Tenacity
uneven to conchoidal
Color
dark red to reddish brown
Streak
reddish to brownish
Transparency
transparent to opaque
Optical character
biaxial (-)
Refractive Index
nα=1.940; nβ=2.200; nΥ=2.510
Birefringence δ
0.570
Pleochroism δ
strong