The way a mineral reflects light

METALLIC: opaque, looks like a metal such as gold, silver, iron, etc.

NON-METALLIC: (needs to be more descriptive)

VITREOUS or GLASSY - strong glint (shiny like glass)

PEARLY (talc, some gypsum) - looks like mother-of-pearl

RESINOUS - reflects light in a manner similar to syrup or tree sap ("glazed")

EARTHY- dull, little or no reflection