Mineral phase
IMA name
Magnetite
Class
non-silicate mineral
Compound type
oxide-hydroxide
Comments
Equivalent Space Group: Fd3m (227)
Formula
Fe2+Fe3+2O4
Chemical formula
(Fe2+)(Fe3+)2O4
Elemental formula
(Fe2+) (Fe3+)2 O4
Isotope mixture type
terrestrial abundance
  Formula Name Family Number min-max Isotope mole fraction State Relevance
Fe2+ Iron(II) cation element 1 constituent element main
Fe3+ Iron(III) cation element 2 constituent element main
O Oxygen element 4 constituent element main
Composition comments
common impurities: Ti, Mg, Zn, Mn, Ni, Cr, V, Al
Oxides
Formula FeO Fe2O3
Mass fraction (%) 31.03 68.97

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
Iron subgroup (07.02.02)
Code
07.02.02.03
Phase type
crystalline
Crystal system
isometric (cubic)
Crystal class
hexoctahedral
Crystal class symbol
m-3m (Oh)
Crystal spacegroup
Fd-3m
Molar mass
231.54 g/mol
Density
5.1 - 5.2 g/cm3
State NTP
solid
Refringence type
isotropic
Refringence sign
no
Birefringence
0
Refraction index nα
2.42
Pure color
black
Color
grayish black, iron black
Diaphaneity
opaque
Luster
metallic