sapphire

Sapphire refers to all gem varieties of Corundum, excluding the red variety of Corundum which is classified as Ruby. In the gem trade, it refers specifically to the blue gem variety of Corundum, unless a color is mentioned as a prefix to sapphire (i.e. Green Sapphire). Sapphire with a color other than blue is often called a "fancy" in the gem trade. See the gemstone section on Sapphire for complete details.