WHAT IS DIAMOND DEPTH?
A diamond's depth can be determined by measuring the entire stone's height from the table to the culet and is described in millimeters. The depth percentage measures the ratio of a diamonds depth (from the table to the culet) to a diamonds total diameter. To learn about the ideal depth percentage for each diamond shape, visit our Diamond Shape page. Depth: The height of a gemstone measured from the culet to the table. Determined as a percentage of the overall diameter of the gem.
A DIAMOND’S OPTICAL ATTRIBUTES
When a diamond is polished and viewed face -up, its appearance has three elements: brightness, fire and scintillation. Brilliance is the effect of all the internal and external reflections of white light. Fire results when white light is dispersed into its spectral colors. Scintillation is the
Combination of pattern and sparkle. Grading the cut of a polished round brilliant diamond involves visually determining these elements as well as measuring the stone’s proportions and considering their relationship to each other.
A diamond’s brilliance is the resultant effect of all the internal and external reflections of white light. In general, the brighter a diamond, the higher its grade. The proportions and finish of a skillfully cut diamond maximize its interaction with light. The table percentage, crown angle and pavilion angle are the major factors that determine a diamond’s brightness. When the diamond has the right combinations of table percentages (52 percent to 62 percent), wide range of crown angles (31.5o to 36.5o), and a narrow range of pavilion angles (40.6o to 41.8o) are known to produce amazing
Fire results when the white light entering the stone is dispersed into its spectral colors. Diamond Fire is the most difficult of diamond’s optical qualities to evaluate, especially in diamonds under 0.50 ct. The pavilion angle is the main factor, followed by the crown facets. Generally, the larger the area of crown facets compared with the table, the more fire the stone produces.
Favorable Diamond Brilliance combinations also work to produce fire. A combination with star facet length percentages of 50 % to 60 % and lower girdle facet length percentages of 75% to 80% will display amazing fire and brilliance.
Scintillation has two components: sparkle and pattern. Sparkle is those spots of light that appear when the diamond, the person observing or the source of light moves. Pattern is a little more complex. Pattern is the relative size, arrangement, and contrast of bright and dark areas that result f rom a polished diamond’s internal and external reflections when it is viewed face-up.
The bright areas result f rom surface and internal reflections. The dark areas might represent a loss of light through the diamond, or reflections f rom the diamond - both of which direct light away f rom the viewer’s eye - or they might be reflections of dark objects around the diamond.