Most geologists, including the author of this article, have not thought as deeply about luster as gemologists. If you open almost any mineralogy textbook to the pages that describe a mineral, the luster is usually given as one or two of the adjectives listed above. For example: submetallic to metallic. The author completed the coursework…

Luster is not a diagnostic property. This means that, for most mineral species, luster can vary from one specimen to another. For example: hematite can exhibit a metallic luster, a submetallic luster, or a dull luster. A single specimen can exhibit one or more of these lusters. Because of that, luster cannot be heavily relied…

Many minerals used in commercial products owe their value and popularity at least in part to their luster. The best example is gold. It has a highly reflective metallic luster that resists tarnish. That beautiful luster makes gold the perfect metal for jewelry manufacturing. Today, most of the world’s gold is made into jewelry. Muscovite…

The photographs and descriptions on this page illustrate some of the most common lusters observed in minerals. Metallic Luster Specimens with a metallic luster exhibit the reflectivity and brightness of a metal and are always opaque. The smoother the surface, the brighter their luster, and the higher their reflectivity. When a beam of incident light is reflected…

The luster of a mineral is best observed on a surface that is free of moisture, dirt, tarnish, and abrasion. Geologists in the field usually carry a rock hammer to break rocks so that their true luster and color can be observed. Breakage is usually not necessary when observing the luster of cleaned and cared-for specimens in a laboratory or classroom.…

Luster is a word used to describe the light-reflecting characteristics of a mineral specimen. The luster of a specimen is usually communicated in a single word. This word describes the general appearance of the specimen’s surface in reflected light. Eleven adjectives are commonly used to describe mineral luster. They are: metallic, submetallic, nonmetallic, vitreous, dull, greasy, pearly, resinous,…