Constituent
Name
Spinel
IMA name
Spinel
Class
non-silicate mineral
Compound type
oxide-hydroxide
Constituent abundance in material
Relevance
main - major
Arrangement
single phase
Mass fraction
1.0
Chemical composition
Formula
Mg$_{1.02}$Al$_{1.93}$Si$_{0.03}$Cr$_{0.0087}$Fe$_{0.012}$O$_{4}$
Chemical formula
Mg1.02 Al1.93 Si0.03 Cr0.0087 Fe0.012 O4
Elemental formula
(Mg)0-1 (Al)0-2 (O)0-4
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
$Mg$ Magnesium element 0 - 1 1.0 constituent element main
$Al$ Aluminium element 0 - 2 1.0 constituent element main
$Si$ Silicon element 0 - 1 1.0 constituent element impurity
$Cr$ Chromium element 0 - 1 1.0 constituent element impurity
$Fe$ Iron element 0 - 1 1.0 constituent element impurity
$O$ Oxygen element 0 - 4 1.0 constituent element main
Composition comments
The natural spinel sample has a minor OH content that is not shown in the formula of the chemical composition.
Oxides
Formula $MgO$ $Al_{2}O_{3}$ $SiO_{2}$ $Cr_{2}O_{3}$ $Fe_{2}O_{3}$
Mass fraction (%) 23.45 74.81 0.51 0.5 0.72

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
Aluminium subgroup (07.02.01)
Code
07.02.01.01
Phase type
crystalline
Crystal system
isometric (cubic)
Crystal class
hexoctahedral
Crystal class symbol
m-3m (Oh)
Crystal spacegroup
Fd-3m
Molar mass
142.27 $g/mol$
Density
3.57 - 3.72 $g/cm^3$
Refringence type
isotropic
Refringence sign
no
Birefringence
0
Refraction index $n_{\alpha}$
1.72 - 1.80
Color
dark-red
Diaphaneity
transparent to opaque
Luster
vitreous