Sapphire, September's birthstone, has been the pre-eminent blue gemstone for centuries. Ancient Persian rulers believed its reflection painted the heavens blue. Indeed, its very name in Latin, sapphirus, means blue.

Sapphires are available in every color but red. Sapphire in colors other than blue is often referred to as fancy sapphire. The most valuable sapphires have a medium intense, vivid blue color. The best sapphires hold the brightness of their color under all different types of lighting. Any black, gray, or green overtones mixed in with the blue will reduce a stone's value