Blue Sapphire is one of big three of jewellery colored gemstone. Most valued Blue Sapphires are velvety blue to violetish blue. Blue Sapphire has Mohs hardness 9.0 marking it a hard gemstone to make jewellery. As a member of corundum family, its crystal system is hexagonal (trigonal). Crystals common often barrel shape prisms with flat ends.
The Blue Sapphire has its own sub categories due to color temperature variance. Cornflower, Peacock, Royal, Velvet blues are mostly common colors and Nave blue, Indigo and Twilight takes second rank based on the taste of collectors. Typically Blue Sapphire cut in cushion, round, oval, emerald, pears, briolette, hearts and marquise.
