Constituent
- Name
- Corundum
- IMA name
- Corundum
- Class
- non-silicate mineral
- Compound type
- oxide-hydroxide
- Relevance
- main - major
- Arrangement
- single phase
- Mass fraction
- 1.0
- Formula
- $Al_2O_3$
- Chemical formula
- Al2O3
- Elemental formula
- Al2 O3
- Isotope mixture type
- terrestrial abundance
- Oxides
-
Formula $Al_{2}O_{3}$ Mass fraction (%) 100.0
Strunz
- Class
- oxides - hydroxides - arsenites (04)
- Division
- metal:oxygen = 2:3, 3:5, and similar (04.C)
- Family
- with medium-sized cations (04.CB)
- Code
- 04.CB.05
Dana
- Major class
- oxides and hydroxides (III)
- Class
- simple oxides (04)
- Type
- with a cation charge of 3+ (A+++2O3) (04.03)
- Group
- Corundum-Hematite group (Rhombohedral: R-3c) (04.03.01)
- Code
- 04.03.01.01
- Phase type
- crystalline
- Crystal system
- trigonal
- Crystal class
- ditrigonal-scalenohedral
- Crystal class symbol
- -3m (D3d)
- Crystal spacegroup
- R-3c
- Texture
- monocrystalline
- Molar mass
- 101.96 $g/mol$
- Density
- 4 - 4.1 $g/cm^3$
- Refringence type
- uniaxial
- Refringence sign
- negative
- Birefringence
- 0.008
- Refraction index $n_{\alpha}$
- 1.767 - 1.772
- Refraction index $n_{\beta}$
- 1.759 - 1.763
- Color
- colorless, blue, red, pink, yellow, gray, brown
- Diaphaneity
- transparent to translucent
- Luster
- vitreous