Mineral phase
- IMA name
- Spinel
- Class
- non-silicate mineral
- Compound type
- oxide-hydroxide
- Formula
- $MgAl_2O_4$
- Chemical formula
- MgAl2O4
- Elemental formula
- Mg Al2 O4
- Isotope mixture type
- terrestrial abundance
- Composition comments
- common replacement: Zn, $Fe^{2+}\!$, $Mn^{2+}\!$ in place of Mg; $Fe^{3+}\!$, Cr, Ti, V in place of Al - common impurities: Ca in place of Mg; Zn, Si in place of Al
- Oxides
-
Formula $Al_{2}O_{3}$ $MgO$ Mass fraction (%) 71.67 28.33
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 $g/cm^3$
- State NTP
- solid
- Refringence type
- isotropic
- Refringence sign
- no
- Birefringence
- 0
- Refraction index $n_{\alpha}$
- 1.72 - 1.80
- Pure color
- colorless
- Color
- colorless, pink, red, violet, blue, green, brown, black
- Diaphaneity
- transparent to opaque
- Luster
- vitreous