The depth percentage and table percentage affect the cut grade and sparkle of both lab grown and natural diamonds equally. In fact, the depth and the size of the table have a great impact on the appearance and scintillation of diamonds. Both of these factors also affect the overall cut quality of a diamond. If you are looking for a diamond with intense fire and brilliance, look for a diamond with a table percentage of 54 to 60% and a depth percentage of 59.5 to 62.9%.
What is the "depth" of a diamond?
Diamond depth is the height from the table to the culet of the diamond. In the grading report, there are usually two depths: the first is the actual depth (measurements) in millimeters; the second is the percentage of depth (depth), which indicates the ratio of the depth and width of the diamond.
The process of diamond polishing is as much an art as it is a science. When light is projected into a diamond, the depth of the diamond affects how the light travels and reflects within the diamond. To maximize light return and scintillation, the ideal depth percentage depends on the shape of the diamond and may also be affected by the clarity of its facets.
How extreme depth ratios reduce the brilliance of a diamond
Although the depth percentage of a diamond does not determine the appearance of the diamond, it can reflect the degree of brilliance and value. Especially the facets of the diamond pavilion, the craftsman wants it to be cut to the correct proportion, so that the light can be continuously reflected in the diamond, and finally reflected back to the viewer's eyes at a specific angle. Diamonds that are too dark or too shallow can have a negative effect on the appearance of the stone.
As mentioned above, the ideal depth percentage of a diamond depends on the shape of the diamond. A percentage that is too dark for one shape may be just right for another, and this has a lot to do with facet structure. For example, a princess cut diamond with a depth percentage of 74 to 76% is acceptable and the stone will look attractive. On the contrary, for round diamonds, 65% depth is too much, which will greatly reduce the beauty of the diamond.
What is the "table" of a diamond?
The table is the smooth facet in the middle of the diamond that it exhibits when it is facing upwards. The table is also the largest facet of a diamond and has a very important influence on the brilliance of the diamond.
To calculate the table percentage in grading reports, divide the table size by the average diameter of the diamond's girdle. Thus, a 60% table means that the table covers 60% of the diamond's outline. For round cut diamonds, divide the table diameter by the average diameter of the diamond to get the above values. Consumers can also easily calculate this percentage using the Measurements of the rating report. The table percentage of a fancy-cut diamond can be calculated by dividing the table width (the widest part of the facet) by the widest part of the diamond.
The importance of table size and percentage
The main function of the table facets is to deflect light that penetrates the diamond and to reflect light from the pavilion facets back to the viewer's eye.
Many people mistakenly think that the larger the table percentage, the more sparkling the round diamond will be. But there are other factors that can actually affect the overall brilliance and fire of a diamond.
To put it simply, a large table does not mean that the diamond will look good, and vice versa. But the size of the table can affect the dispersion properties of a diamond's fire. To understand this principle, you must first know that the main facet (Bezel Facet) of a diamond is the part that can best show fire. Due to the limited space of the crown (Crown)*, a larger table naturally means that the surface area of the main facet and the upper-girdle facet (Upper-Girdle Facet) is smaller, and the dispersion will be reduced.
Conversely, a smaller table can give the girdle more dispersion, but the diamond will be less scintillating. So the most important thing is to strike a balance between "light passing through the table" and "dispersion of the crown and upper girdle".
*Crown refers tothe part above the diamond girdle
What is the optimum depth and table for a diamond?
When choosing a diamond, you can refer to the depth and table percentage list below. Shown in the table are some of the more popular shapes.
For round cut diamonds, 54 to 60% table and 59.5 to 62.9% depth are ideal.
How to effectively apply depth and table percentages?
The combination of depth and table percentage can have a significant impact on a diamond's appearance. You can see whether the cut of the diamond is in accordance with the proportions. These values can let you know whether the cut of the diamond is ideal at the first time. Variations in a diamond's brilliance may be visible to the naked eye alone, but differences in proportions are less noticeable. These values and percentages are the advanced criteria for distinguishing good and bad diamonds.