Constituent
Name
chromite
IMA name
Chromite
Class
non-silicate mineral
Compound type
oxide-hydroxide
Comments
Equivalent Space Group: Fd3m (227)
Constituent abundance in material
Relevance
main - major
Arrangement
single phase
Chemical composition
Formula
$Fe^{2+}\!Cr_2O_4$
Chemical formula
(Fe2+)Cr2O4
Elemental formula
(Fe2+) Cr2 O4
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Fe^{2+}$ Iron(II) cation element 1 constituent element main
$Cr$ Chromium element 2 constituent element main
$O$ Oxygen element 4 constituent element main
Composition comments
common impurities: considerable amount of Mg replacing $Fe^{2+}$ and Al, $Fe^{3+}$ replacing Cr, other impurities: Zn, Mn, Ti, V
Oxides
Formula $Cr_{2}O_{3}$ $FeO$
Mass fraction (%) 67.9 32.1

Strunz

Class
oxides - hydroxides - arsenites (04)
Division
metal:oxygen = 3:4 and similar (04.B)
Family
with only medium-sized cations (04.BB)
Code
04.BB.05

Dana

Major class
oxides and hydroxides (III)
Class
multiple oxides (07)
Type
(A+B++)2X4 Spinel group (07.02)
Group
Chromium subgroup (07.02.03)
Code
07.02.03.03
Phase type
crystalline
Crystal system
isometric (cubic)
Crystal class
hexoctahedral
Crystal class symbol
m-3m (Oh)
Crystal spacegroup
Fd-3m
Molar mass
223.84 $g/mol$
Density
4.5-5.09 $g/cm^3$
Refringence type
isotropic
Refringence sign
no
Birefringence
0
Refraction index $n_{\alpha}$
2.08 - 2.16
Color
black, brownish black
Diaphaneity
opaque
Luster
metallic