The richness or intensity of reflections of white light in the face-up position of the crystal. The reflections will increase with a well-cut crystal since the light is contained for a longer period of time before being allowed to escape toward the viewer’s eyes (as compared to a poor-cut).
Relates to a crystal’s ability to refract (bend) white light, displaying the spectral colors, red, orange, yellow, blue and green. Most transparent materials will bend light, but diamond’s refractive index is exceptionally high, thus producing more distinct colors in the overall light spectrum. In diamond’s case, this is more commonly marketed as “fire”
The movement of the reflections (brilliance) and dispersion (spectral colors), as the diamond (or other gemstone) is rotated or tilted before the viewer’s eyes.
The good news is advancement in both cutting and coating technology has allowed manufacturers to create the diamond look as a fraction of a diamond’s cost.