Corundum vs Diamond
Corundum and Diamond are genuine alternatives to one another — a choice somebody actually makes — and differ on 4 measured properties, crystal system most clearly.
Corundum vs Diamond
Corundum
Al2O3
Aluminium oxide — hardness 9, the mineral of ruby and sapphire, and a major industrial abrasive.
Diamond
C
Carbon in a cubic lattice — the hardest naturally occurring substance, and one of the best thermal conductors known.
| Property | Corundum | Diamond |
|---|---|---|
| Crystal system Categorical values can be listed side by side but not ordered or subtracted. | trigonal | cubic |
| Density | 3.95–4.1 g/cm³ higher | 3.5–3.53 g/cm³ |
| Lustre Categorical values can be listed side by side but not ordered or subtracted. | vitreous to adamantine | adamantine |
| Mohs hardness Mohs hardness is an ordinal scale: values can be ranked, but differences and ratios between them are not meaningful. | 9 | 10 higher |
| Refractive index Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 2.417 |
| Thermal conductivity Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | 900–2320 W/(m·K) |