The birthstone for September is sapphire, a variety of the mineral corundum. Sapphire derives its name from the Greek word for blue stone. Sapphire is one of the hardest gemstones, measuring 9.0 on the Mohs hardness scale. Royalty have long associated sapphire with nobility, sincerity, and faithfulness. Sapphire is found in countries around the world and can come in various colors, though blue is most common. Ancient cultures believed sapphire provided spiritual enlightenment and healing properties.