Although many default to the color blue when "sapphire" is mentioned, it is not only blue. The term sapphire describes any color variety of the mineral corundum that is not red, being that red corundum is defined as ruby. Sapphire may be blue, yellow, pink, orange, green, purple, or colorless. It is especially rare in its orange variety, often accompanied by a pink hue, called padparadscha, which is Sinhalese for lotus flower. A trace amount of chromium is responsible for the pink and red varieties of corundum, while the presence of iron and titanium contribute to the more common blue sapphire.

Asterism, a star-effect, may appear on the surface of a piece of properly cut cabochon corundum. The gem is then classified as a "star sapphire" (if not red) or "star ruby" (if red). Major sapphire mines are found in Sri Lanka, Tanzania, Madagascar, Thailand, Myanmar, and Australia.