Sapphire is the most precious and valuable blue gemstone. It is a very desirable gemstone due to its excellent color, hardness, durability, and luster. In the gem trade, Sapphire without any color prefix refers to the blue variety of the mineral Corundum.

SriLanka is world famous for Blue Sapphires with most of the largest sapphires in museum collections from around the world being from here. They are widespread and occur mostly among the secondary sedimentary deposits as water worn pebbles.

Mineral Blue Sapphire
Chemistry Al2O3
Refractive Index 1.762 to 1.770
Birefringence 0.008 to 0.010
Specific Gravity  4.00
Mohs Hardness  9
BirthStone September