Ruby is a precious gem and belongs to the Corundum family, just like Sapphire, chemical composition Al2O3. It’s hardness is 9 on the Mohs scale. The most prized is the red « pigeon blood » and it exist in other hues such as pinkish red, slightly purple, etc…As a result of its rarity when it is pure of a beautiful red color, the Ruby is subjected to many treatments. Most of the time, Rubies are heated with lead glass for filling fractures and improve color. This heavy treatment therefore considerably decreases it’s value. Without treatment, rubies are very expensive.