Lustre (or luster) is a term that describes how light reflects off of a rock or mineral. This detail must be observed first hand and noth through a photograph, video, or otherwise.

List of types of luster:Edit

Metallic - strong reflection, shines like metal, may be very shiny (like a chrome car part) or less shiny (like the surface of a broken piece of iron);
Vitreous - glassy, bright (shines like glass);
Resinous - a resin-like shine (for example: resembling amber);
Greasy - a dull sheen, has the appearance of being coated with an oily substance;
Pearly - a whitish iridescence (for example resembling a pearl);
Silky - a sheen like that of a fibrous material, e.g. silk;
Adamantine - a brilliant lustre such as that of diamond;
Earthy - like the surface of unglazed pottery