Sapphire, a mineral twin of ruby, is also a crystallised form of corundum, with colours ranging from blue to orange, through green, right down to yellow and pink, but it lacks a few chrome atoms to acquire the red colour of ruby. 
The attraction of sapphire comes from its celestial colour harbouring much symbolism. This stone adorned the headdress of Kings or the talisman of Emperors. 
Sapphire deposits are found in Myanmar, Thailand, Australia, Sri Lanka, etc.