Ruby is the red variety of corundum. It is bright red to pink, but the lighter pinks are often referred to as pink sapphire. All other colors of corundum are called sapphire. The brilliant, clear, red corundum known as pigeon's blood red, is the most valuable color, especially if it is clear and pure. But many rubies are darker or cloudy to opaque, often with small black inclusions, and very affordable and lovely. Ruby is classified as a precious stone.
