September's birthstone is the (traditionally) deep blue sapphire. An ancient stone, the sapphire is modest, faithful and full of wisdom and protection. Sapphire adorned kings, religious leaders and warriors in ancient times. Also, blue sapphire was a traditional stone for engagement rings, representing commitment, fidelity, and love.
Sapphire actually forms in a rainbow of colours in a unique bipyramidal shape. The mineral that forms with aluminium oxides determines the particular colour of each sapphire. Red sapphire is actually what we consider ruby!