How a diamond has been cut, polished, and to what proportions and symmetry, are of utmost importance since these factors determine the life, brilliance and dispersion of the diamond. If these cutting factors fall below standard, the appearance of the diamond will be adversely affected.

Reflection Refraction Dispersion
Reflection Refraction Dispersion

A) When a ray of light touches the surface of a diamond, part of the light is reflected back, this is external reflection.

B) The rest of the ray penetrates the stone and is then reflected toward the center of the diamond. This is known as refraction.

C) The ray of light is reflected to the surface, where it is seen as the colors of the spectrum. This is known as dispersion.

Execution of the design, the precision of the cutting details and the quality of the polish are collectively called the finish.

Reflection, refraction, and dispersion, demonstrated in one animated illustration