Diamond certificates have become an essential part of the diamond trade. Originally, diamond certificates were mainly required by professionals, but in recent years consumer demand is growing steadily too.

To fully appreciate a stone, information is needed and this can be found in a diamond certificate. A certificate is of course only useful if it is reliable. The HRD, like the IGI and GIA certificate enjoys an excellent reputation for objectivity and quality.

A diamond certificate first of all guarantees the authenticity of the diamond. In other words: the document confirms that the stone described is indeed a natural diamond, and for example not an imitation or a synthetic material. Therefore, the authenticity is the first thing to be checked in the lab. The certificate furthermore contains a complete quality description of the diamond. These quality characteristics determine the value of the stone.

For example the HRD certificate mentions : shape, weight, clarity grade, fluorescence, color grade, measurements, proportions and finish grade, possibly supplemented with comments. The main quality characteristics are referred to as the 4 Cs:Carat (weight), Clarity, Color and Cut.


Fluorescence is the effect whereby invisible ultraviolet light is transformed into visible light. Some stones light up spectacularly in the dark when irradiated by long-wave ultraviolet light.

The color of the fluorescence is usually blue, but other colors are possible too. Normal daylight contains a certain amount of UV-light, and therefore the fluorescence can influence the color of the stone.

The fluorescence grades are : nil, slight, medium and strong.


The proportions, the relationship between the various parts of the stone, determine the fire and brilliancy of the diamond. If the proportions are not optimal, undesirable visual effects may occur. The main symmetry-deviations and the proportions are judged on the basis of objective, measured data.

Finish grade

When examining the finish grade, attention is mainly paid to possible symmetry deviations and facets. A good finish grade testifies of the workmanship of the diamond polisher.