Diamond Brilliance
Just as color grading defines the degree of colorlessness and clarity grading defines the degree of flawlessness, cut grading addresses the degree of a diamonds brilliance. The following describes the elements of brilliance.
FLASH:
The adamantine (hard due to molecular density) surface of a polished diamond provides for an optimal reflection of environmental light from diamonds exterior surfaces. The top of a diamond (crown) is composed of one large center facet, the table and bordered around by smaller crown facets. When the table is too large and/or the surrounding crown facets are too relatively small or their degree of angle is too steep, flash overpowers the appearance of refracted, prismatic fire light from within the diamond.
DISPERSION:
The refracted colors of diamond light are the result of white light being bent, as it travels through the molecularly dense crystal structure, to reveal the component rainbow of colors that compose white light. When a diamond is cut too deep, increasing the degree of the pavilion (bottom) angle this prismatic light, diamonds fire, increasingly leaks out the sides of the diamond rather than being returned to the top (crown) and the viewers eye.
BLEND:
The balance of flash and fire is a function of the depth and degree of angle of the pavilion and the height and degree of angle of the crown facets and the resulting size of the table (top center facet) of each diamond. Optimally we want to see an even blend of flash and refracted light across the entire field of vision of the crown of the diamond.
SCINTILLATION:
The dance of twinkling light, optimally in an evenly distributed pattern across the field of vision of the crown of the diamond, is a function of the movement of the diamond and/or the movement of the viewer as light plays from one exterior and/or interior facet to another.
BRILLIANCE:
The total effect of flash, dispersion, blend and scintillation are the component parts of a diamond’s brilliance.
You must know the diamond's true proportions to make an objective assessment of cut:
- Depth and pavilion angle guides our understanding of the total amount of refracted light (fire) within the diamond that is returned to the eye.
- Table percentage and crown angle guides our understanding of the blend of environmental light (flash) from the exterior crown facets and fire from within the diamond.
- The girdle is the critical interface between diamond crystal and the jewelry mounting and is the most carat intensive portion of the diamond.
- The polish and symmetry grades disclose the care with which the blocker and brillianteer have crafted each diamond.
Each shape of a diamond, be it round, emerald cut, pear, princess, oval, heart or marquis has its own unique set of proportional values that determine the brilliance of diamonds in that shape. And finally, we have seen the diamond grading contributions of the leading experts in the field, including Mr. David Atlas and associates of The Accredited Gem Appraisers, The Gemological Institute of America and The American Gem Society and International Gemological Institute. Diamonds are widely studied with diamond grading research being ever improved by the contributions these professional men, and women.
LEARN MORE:
Diamond Color | Diamond Clarity | Diamond Cut | Diamond Carat | Beyond the 4Cs | Diamond Brilliance | Ideal Cut Diamonds | Diamond Grading Systems