Luster is the physical
property which describes the appearance of reflected light from fresh mineral
surfaces. Luster is divided into two basic categories: metallic and nonmetallic.
Metallic minerals are opaque and look like refined metals such as steel,
brass, silver, or gold. Nonmetallic minerals may be opaque, translucent,
or transparent, and are further describes as being adamantine (brilliantly
reflecting), vitreous (bright and shiny such as broken glass), earthy (dull),
waxy, resinous, pearly, silky, and greasy.
