In the gem trade, the term light performance is used to describe how well a polished diamond will return light to the viewer.

There are three light properties to light performance: brilliance, fire, and scintillation.

• Brilliance refers to the white light reflections from the external and internal facet surfaces.
• Fire refers to the spectral colors which are produced as a result of the diamond dispersing the white light.
• Scintillation refers to the small flashes of light that are seen when the diamond, light source or the viewer is moved.