lustre (mineralogy)

For other senses of this word, see lustre.Lustre (American English: luster) is a description of the way light interacts with the surface of a crystal, rock, or mineral. For example, a diamond is said to have an adamantine lustre and pyrite is said to have a metallic lustre. The word luster traces its origins back to the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance.
See more at Wikipedia.org...