Sapphire is any colour of the mineral corundum other than red, which is called ruby. Corundum is composed of aluminium oxide. Sapphires tend to be translucent or transparent and have high amounts of refraction. The most desirable sapphires are generally those with an intense blue colour with plenty of sparkle and life. Various shades of blue result from titanium and iron substitutions in the aluminium oxide crystal lattice. They can be found in Brazil, Tanzania, Sri Lanka, Kashmir, Thailand, Madagascar and Australia. Source: Encyclopedia of gemstones and minerals.