Luster — Science definition
Defined in 2 courses:
- How a mineral's surface reflects light — described as metallic (shiny like metal) or non-metallic (glassy, pearly, dull, or earthy). (Earth & Space Science)
- The shiny appearance of a polished metal surface. (Physical Science: Chemistry)
Where it is taught
- Minerals & Their Properties — Rocks, Landscapes & Water, Earth & Space Science, Grade 9
- Metallic Bonding — Bonding, Formulas & Molecular Structure, Physical Science: Chemistry, Grade 11
In use
Luster describes the way a mineral's surface reflects light — is it metallic, gleaming like a polished spoon, or non-metallic, looking glassy, pearly, waxy, dull, or earthy?
Minerals & Their Properties
The mirror-bright luster of a polished metal comes from those same free electrons: they readily absorb light and re-emit it, bouncing it back to your eye as a shiny surface.
Metallic Bonding
Questions using luster
Problem 1
The shiny luster of a polished metal surface is explained by…
- its rigid ionic lattice
- the free electrons absorbing and re-emitting light
- the metal's very high density
- electrons that are tightly bound to each atom
Answer and explanation
the free electrons absorbing and re-emitting light
The delocalized electrons readily absorb light and re-emit it, reflecting it back to give a shiny surface.