Luster

Luster is a description of the way light interacts with the surface of a crystal. This is how you would tell someone how a mineral looks. It has nothing to do with color or shape, but is related to transparency, surface conditions, crystal habit and index of refraction. The terms used are generally not scientific, but are meant to be descriptive. Most are self explanatory.

The list below includes the most commonly used terms, however other unique terms are sometimes used for unique minerals or specimens.

• Adamantine - very gemmy crystals (shown above)
• Dull - just a non-reflective surface of any kind
• Earthy - the look of dirt or dried mud
• Fibrous - the look of fibers
• Greasy - the look of grease
• Gumdrop - the look of a sucked on hard candy
• Metallic - the look of metals
• Pearly - the look of a pearl
• Pitchy - the look of tar
• Resinous - the look of resins such as dried glue or chewing gum
• Silky - the look of silk, similar to fibrous but more compact
• Submetallic - a poor metallic luster, opaque but reflecting little light
• Vitreous - the most common luster, it simply means the look of glass
• Waxy - the look of wax