The luster of a mineral is the way its surface reflects light. Most terms used to describe luster are self-explanatory: metallic, earthy, waxy, greasy, vitreous (glassy), adamantine (or brilliant, as in a faceted diamond). It will be necessary, at least at first, only to distinguish between minerals with a metallic luster and those with one of the non-metallic lusters. A metallic luster is a shiny, opaque appearance similar to a bright chrome bumper on an automobile. Other shiny, but somewhat translucent or transparent lusters (glassy, adamantine), along with dull, earthy, waxy, and resinous lusters, are grouped as non-metallic.