Corundum

Corundum, which is also called crystal alumina, is an aluminum oxide. In industry, corundum is used in form of abrasive emery in form of plain powder. The nodular samples of corundum are good abrasive material, which is used in production of polishing and grinding powders as well as for production of refractory materials. Corundum is also used as a decorative stone: its transparent crystals possessing beautiful color can be used as insertions into jewelry. Corundum is also used in production of watches.
corundum

Formula for Corundum

Al2O3

Formula for Corundum

Properties for Corundum

Molar mass: 101.96128 ± 0.00090 g/mol
Melting point: 2,072 °C (3,762 °F; 2,345 K)
Boiling point: 2,977 °C (5,391 °F; 3,250 K)
Density: 3.95–4.1 g/cm3