JEWELRY EDUCATION > GLOSSARY > Ruby
Ruby is the red variety of transparent corundum and is one of the most prized precious gemstones. All colors of corundum, except red, are known as sapphires, which has can cause doubt about where ruby ends and sapphire begins, particularly in pink shades. However, lighter shades of reddish hues should be included in the ruby category. The finest rubies are more costly than diamonds of the same size, and are exceeded in value only by the emerald.