Blue, the color most often seen in sapphires, belongs in everything that is constant and reliable. That’s why women often wish for a sapphire ring on their engagement. The top sapphires from Kashmir feature a pure , intense blue with a fine, silky glow.
Formula: Al2O3
Hardness: 9
Density: 3.90 – 4.05 g/cm3
Refractive Index: 1.760 – 1.772 DR: 0.008 http://www.shapur.com/sapphire/
Color:
Greenish-blue, blue, violet-blue
Countries of Origin:
India (Kashmir), Myanmar, Sri Lanka, Madagascar, Thailand, Cambodia, Tanzania, U.S.A., China
Birthstone: September