Other parameters of diamond certificate



In addition to looking at the diamond 4C, there will be a lot of other parameters on the certificate, it will affect the quality of a diamond. And the above words believe that many of the non diamond related industries, it is very strange.

So for those of us outside the pedestrian, GIA certificate how to look at it?

Here to give you more details on the certificate on the other parameters of the information bar.



How smooth diamond polishing directly affect the diamond, which determines the diamond cutting effect. The diamond polishing effect has a direct influence on the optical effect of diamond. If the surface of the diamond is not smooth, then the light will produce a slow reflection, resulting in the performance of the diamond dull color, reflecting the light is dim or unclear. Diamond polishing is divided into: ID (standard), EX (excellent), VG (very good), G (good) and other four levels.

The higher the hardness of the diamond, grinding and polishing the more difficult, but after polishing, the diamond will be more smooth. The reason is that the hardness of the diamond increased, in order to achieve a lower roughness, the polishing time required for a corresponding increase. The advantage is that the higher the hardness of the diamond, the possibility of polishing is relatively reduced.


The symmetry of the center points of each part of the diamond cutting and grinding, that is, the arrangement of angles and the angle of each other. The same as the ratio of the important indicators for evaluation. If Turner and the proportion of a diamond is excellent, symmetrical cutting will make flash and fire more strongly. Foreign certification on the symmetry of the more detailed, from high to low in turn ideal (ID), excellent (EX), very good (VG), fair (F), poor (P).


Round brilliant cut diamonds, with average girdle diameter percent from the waist edge surface to the bottom tip of the vertical distance.
GIA standard round hole depth ratio of about 43% is the best.
Formula: Pavilion depth ratio = Pavilion depth / average diameter x 100%


Diamond table size is a factor that can directly affect the degree of reflection of diamonds. Table size is expressed as a percentage (the ratio of the width of the table to the average diameter of the diamond). Compared with the bottom crown angle, table size of diamond effect is not so big and beautiful. The new system of AGS and GIA are used is 61% perfect cut (AGS can be even less than 47%).


The fluorescence index refers to the diamond will be issued blue or yellow light and light intensity in the strong ultraviolet rays. In other words, in the natural light, we can not feel it, unless in the intense ultraviolet light in the summer sun, with a strong fluorescent diamond, we can see the presence of the naked eye fluorescence. GIA standard: none (no), faint (weak), mediumblue (medium blue) /medium yellow, strong blue (moderate yellow) (strong blue) /strong yellow (yellow) level, the level of fluorescence of D G diamond color is above VS grade 50 and above the price of diamonds was greatly affected medium, fluorescence will affect the price of about 5%-10%, 30% cheaper or more strong fluorescence, particularly strong fluorescence basic than non fluorescent prices about 35% lower.