Glittering Stones >> Semi Precious Stones >> Corundum

Semi Precious Stone Corundum

Corundum is the second hardest natural mineral according to science. The hardest mineral, diamond is still four times harder than the corundum. The hardness of corundum could be partially attributed to the strong and short oxygen-aluminum bonds. These bonds pull the oxygen and also aluminum atoms close together, making the crystal not only hard but quite dense for the mineral made up of two relatively light elements.

Historical Facts of Corundum

Refractive index: 1.768 - 1.772, 1.760 - 1.763

Hardness: 9

Category: Mineral

Chemical Composition: Trigonal Hexagonal Scalenohedral

Color: Brown, yellow, red, blue and violet colors

Major varieties: Sapphire, Ruby, Emery

Precious corundum Jewelry