There are four aspects of a polished diamond that directly relate to the stone’s optical and physical properties. These factors are luster, brilliance, dispersion, and scintillation and they are greatly impacted by the way the diamond is cut.
LUSTER: Luster can be described as the quality and amount of light that is reflected off the surface of a diamond. It is directly related to the hardness of the stone and the quality of its polish. A well polished diamond is the most lustrous material on earth because diamond is also the hardest material known to man.
BRILLIANCE: Brilliance refers to the amount of white light that is returned to the eye from both internal and external surfaces. The amount of brilliance you see coming from inside a diamond is determined by the quality of the stone’s polish the number and size of any inclusions inside the gem. External brilliance is controlled solely by the quality of a stone’s polish. In that regard, brilliance and luster are closely related.
DISPERSION: Dispersion is sometimes called the diamond’s fire. Dispersion is the display of spectral or rainbow colors seen coming from the inside of a diamond. The amount of fire produced in a diamond is directly related to how well the stone is proportioned. A well-cut diamond will offer a pleasing balance between dispersion and brilliance.
SCINTILLATION: Scintillation is just a big word for sparkle. A diamond will show scintillation or sparkle only when movement is involved. The diamond, the light source, or the viewer must be in motion for scintillation to happen. A well-cut diamond in motion is absolutely the most dazzling gemstone in the world.