Ruby

Chemical Formula

Al2O3

Chemical Class

Oxides

Properties

Ruby is a precious variety of Corundum, a high hardness mineral, losing only to Diamond. Ruby red color is caused by lower Cr (chrome) quantities, replacing Al (aluminum) in crystal structure.

Origin

Sabinópolis, MG

Curiosities

This corundum variety is used as gemstone, but it can also be blue, and this other variety is known as Sapphire.

Use

Due to its high hardness, it was widely used as abrasive and for polishing, and it has been modernly replaced by synthetic abrasives. It is also used in precision mechanisms, including special watches and engines. Mineral, gemological and collection species

ABC of mining