More about certification

Strict anonymity and objectivity

The absolute objectivity of the grading results is guaranteed by means of a double coding system: one set of codes is given to the owner, while the other follows the diamond in the lab. Strict anonymity guarantees strict objectivity.

Quality that inspires confidence

The integrity of the grading process is absolute. The Diamond Lab applies an uncompromising operating code which it supports by using some of the most sophisticated technology and qualified graders that work in the trade. It is constantly kept up-to-date on the latest developments and innovations in the profession by HRD Antwerp's extensive in-house Research department.

The results of the examinations performed are based on scientific methods and observations made in the Diamond Lab and in the labs of its partnering universities.

The 4 C's of diamond

The quality of a diamond is defined by means of the 4 Cs: carat, colour, clarity and cut. These four characteristics determine your diamond's value. And, as every diamond is unique, they are also very useful for identification.


The weight of a diamond is expressed in carats. One carat equals 0.2 grams or 100 points. Each diamond is weighed immediately upon receipt at the reception desk. HRD Antwerp has extremely accurate scales that measure up to 1/100,000 of a gram. This accurate weight is very useful for the identification of the diamond


Most diamonds range in colour from white to slightly yellow. However, diamonds can occur in all sorts of colours ranging from brownish to yellow, pink, purple, red and blue. These are called 'fancy colours'


All diamonds have traces of their growth history. The clarity scale reflects the size, number, location and visibility of the internal characteristics when examined with a 10x loupe.


A diamond's cut is essential to its beauty. If the diamond is not well-cut, the diamond will not interact with light as it should. Even a diamond with outstanding colour and clarity will not display the fire and brilliance that diamonds are famous for.

Since January 2009, HRD Antwerp has refined its cut grade, and now grades the diamond's proportions, polish and symmetry. The polish describes the finish of the facets, while the proportions determine the brilliancy and the fire of the diamond. The symmetry describes the variations of the different parameters that define the proportions. Each grade is divided into 4 categories: Excellent, Very Good, Good and Fair.

For more information on HRD Antwerp's refined cut grade, please download the leaflet..