Sapphire is a precious gemstone and a variety of the mineral corundum, most famous for its deep blue color caused by traces of iron and titanium, though it occurs in nearly every color except red (which is ruby). It boasts a hardness of 9 on the Mohs scale, second only to diamond, making it highly durable for everyday jewelry. Symbolizing wisdom, loyalty, and nobility, sapphire is the traditional birthstone for September and has been revered in cultures worldwide for millennia.