Luster refers to the quality and quantity of light reflected from a gemstone’s surface. It is what gives gemstones their shiny, glass-like appearance. Most gemstones have luster and all metals have luster. There are two main types of luster: metallic and nonmetallic. Nonmetallic luster is broken down into several subtypes of luster: vitreous, resinous, pearly, greasy, silky, adamantine, dull, and wax. For gemstones, the most common luster is vitreous luster.
