The 8 Quality Criteria and the rule of the 4C’s

While the beauty of an visual attraction to a precisely cut stone can vary from one person to another, the actual value is based on well defined international standards.

The Rule of the 4 C’s

It is the rule that grades the stone based on four criteria that start (in English) with the letter C:

1.Carat (the weight) - 1 carat equals 0,2 gram

(please note that the actual size may vary due to different screen resolutions)

2. Clarity

Clarity grades are determined by the size, position, brightness and number of inclusions.

3. Colour

(Please note that this image is only meant to show the different shades, real diamonds can look different)

En plus de ces nuances de couleur, il faut tenir compte d’un autre critères qui a un rapport avec la couleur : la fluorescence ( voir plus loin )

4. Cut

The most common shapes found in diamonds

The same criteria are used by experts all over the world to evaluate precious gems.

Together these criteria give the possibility to evaluate the stone in terms of value, using a fixed standard.

The 8 quality criteria of a diamond

For diamonds 4 additional criteria are used, because they have a large effect on it’s value:
5 - Proportions
6 - Symmetry
7 - Quality of the Polish
8 - Degree of Fluorescence

The higher the diamond scores on all the criteria, the higher it’s value.

The official certificates (delivered by the HRD, GIA or IGI) must accompany every quality stone to refer to it’s score on the 8 criteria. This certificate is the best way to guarantee the authenticity and quality of the stone and gives the diamond industry the possibility to trade stones worldwide without having to review every single stone by hand.

Therefore we state that grading a diamond only by the “4C” is not sufficient, for the estimation of it’s exact value it is of major importance to look at the other four criteria. Sadly those four criteria are often not mentioned.

Private Diamond Club only offers diamonds that answer to the following criteria:

- Proportions : Good, Very Good or Excellent
- Symmetry : Good, Very Good or Excellent
- Quality of polish : Good, Very Good or excellent
- Degree of fluorescence : Nil or Slight