Luster: Light reflected from the surface of a mineral Luster Type                     Luster Description Adamantine                             High index of refraction Earthy (Dull)                           Completely dull, found often in clays Greasy (Oily)                          Surface alteration Metallic                                   Specular reflection Resinous                                  Luster of resin Schiller                                    Caused by numerous platy inclusions or separations Sub Metallic                             Almost metallic reflection Subadamantine                        Not quite adamantine in luster Vitreous (Glassy)                     Luster of broken glass Waxy                                       Fairly dull luster similar to wax

     Sheen: Light reflected from the internal structures of a mineral