Aluminium oxide vs Ruby
Aluminium oxide and Ruby share a composition and differ on 1 measured property — the question a reader asks about any pair of polymorphs.
Aluminium oxide vs Ruby
These are different kinds of thing (compound, mineral variety). Fewer properties mean the same thing across both, so a like-for-like reading may not be available.
Aluminium oxide
Al2O3
Industrial alumina — the refined intermediate between bauxite and aluminium metal, and a major ceramic in its own right.
| Property | Aluminium oxide | Ruby |
|---|---|---|
| Crystal system Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | trigonal |
| Density | 3.987 g/cm³ | 3.97–4.05 g/cm³ higher |
| Melting point Only one of the two has a figure we can stand behind, so there is nothing to compare. | 2072 °C | Not known |
| Mohs hardness Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 9 |
| Molar mass Only one of the two has a figure we can stand behind, so there is nothing to compare. | 101.96 g/mol | Not known |