Aluminium Oxy Hydroxide
AlO(OH)
Chemical name
Aluminium Oxy Hydroxide
Mineral name
Diaspore
Chemical formula
AlO(OH)
Crystal system
orthorhombic
Crystal Class
orthorhombic-dipyramidal (2/m 2/m 2/m)
Space Group
Pbnm
Unit cell
a [Å]:4.40
b [Å]:9.42
c [Å]:2.84
Molecular weight [g/mol]
59,97
Formula units
Z=4
Twinning
twinning on {021} or pseudohexagonal aggregates
Mohs hardness
6.5 - 7
Density [g/cm3]
3.3 -3.5
Cleavage
perfect on {010}, distinct on {100} and indistinct {100}
Fracture / Tenacity
conchoidal
Color
white, pale gray, colorless, greenish gray, brown, pale yellow, pink, purple
Streak
white
Transparency
transparent to translucent
Optical character
biaxial (+)
Refractive Index
nα=1.682-1.706; nβ=1.705-1.725; nΥ=1.730-1.752
Birefringence δ
0.048
Pleochroism δ
strong