Zinc Ferrite Zinc Iron Spinell type
ZnFe2O4
Chemical name
Zinc Ferrite Zinc Iron Spinell type
Mineral name
Franklinite
Chemical formula
ZnFe2O4
Crystal system
cubic
Crystal Class
cubic-hexoctahedral (4/m -3 2/m)
Space Group
Fd-3m
Unit cell
a [Å]:8.42
b [Å]:8.42
c [Å]:8.42
Formula units
Z=8
Frequent crystal surfaces
{111}, {100}, {110}
Twinning
on (111)
Mohs hardness
6 - 6.5
Density [g/cm3]
5.07 - 5.22
Cleavage
on {111}
Fracture / Tenacity
conchoidal, uneven/irregular
Color
black
Streak
reddish brown to black
Transparency
opaque
Optical character
isotropic
Refractive Index
n=2.35
Pleochroism δ
none