pictogramme de diamant

The sale of a diamond cannot be improvised. To appreciate its value, you should first know how to estimate it.


Criteria for evaluating a diamond :

There are four main criteria to consider when buying a diamond : the 4 Cs

The weight of the diamond is one of the most important criteria. Expressed in carat, the value of one carat being 0.20 grammes.

The clarity of the diamond which is noted from “IF” to “P” can only be established by appraisal from a diamond merchant. This is assessed by the number and the position of inclusions in the stone. An “IF” stone is the highest clarity while an included stone corresponds to the lowest degree of clarity.

The colour of the diamond is also a key criterion to evaluate when selling a diamond. A scale is used for this ranging from D for snow white to Z for a strong yellow. To determine the colour, place your diamond on white stock card.

To sell your diamond, the quality of the cut is also very important. A coloured diamond does not necessarily need ideal proportions; above all, it is a matter of taste. Nonetheless, certain proportions should be respected to give the diamond its sparkle. On the other hand, for white diamonds, the current trend requires a minimum of 3 “Very Good” , or even 3 “Excellent” scores in Proportion, Cutting and Symmetry. This guarantees optimal brilliance. “Good” proportions, on the other hand, give a dull appearance to the stone: these are often flat stones.


presentation of 4 different shaped white diamonds


Diamond fluorescence : choose a diamond with “none” (or “nil”), “slight” fluorescence solely for D, E, F and G colours. Avoid diamonds with “strong” fluorescence that will give the stone a milky appearance. Choose “strong” fluorescence for H, I, J colours etc., as this will improve the brilliance and colour of the stone.


Diamond purchase security :

When choosing your diamond, it is best to use a lamp that produces a light that is as close as possible to daylight. In most jewellers, yellow spectrum lamps are used ; they enhance the diamond, but only artificially. Once outside, in the daylight, the diamond suddenly sparkles a lot less ! It is essential to choose your diamond using a “cold” light that reproduces the conditions of outdoor, northern light between 12 and 2 pm.

The certificate should accompany your diamond. This gemmological report includes all the main features of the diamond and it is a real identity card for your stone. We recommend the following laboratories: GIA, HRD and IGI.


logo of laboratories GIA HRD IGI

Laser engraving the certificate number on the girdle (the circumference) of the diamond is a must. This means your diamond is fully traceable. You will be able to recognise your stone by yourself with a magnifying glass that enlarges 20 times.

Beware of treated and HTHP stones. We only supply natural diamonds ; the certificates will confirm this.

Be warned that “Clarity enhanced” or “Colour enhanced” diamonds have been artificially modified (clarity or colour). The price of such diamonds drops considerably (by 70 to 80%).

An individual who purchases a diamond without a certificate takes the risk of unknowingly purchasing a treated stone !


Choosing a diamond :

We advise you to choose a diamond with clarity ranging from IF (pure) and VS2 and a colour between D and F if you are opting for “investment diamond”.
A VVS or pure diamond will gain more financial value than another with VS or SI clarity.
If you are looking to indulge in a diamond to wear on a daily basis, clarity between VS2 and SI2 is suitable.
As regards the colour, stay with D, E, F and G if the diamond is mounted on white gold or platinum.
For yellow gold, H and I colours are suitable, as yellow gold makes the stones seem whiter than they are.

It is also important to buy a diamond at market prices.

A price list for cut diamonds called the «Rapaport Diamond Report » is available by subscription for professionals. This list gives the prices for all diamonds from 0.01 carat to 10 carats according to their weight, colour, clarity and cut shape. It is used every day by diamond cutters and merchants worldwide for their transactions. It concerns diamond prices.

Our advice : What is important is to choose a ‘lively’ diamond for which you have a ‘feeling’. A well-cut, white diamond will sparkle all year even when the sun is not out.

Please contact us for any request or if you want to make an appointment. We welcome you from Monday to Friday from 9.30 am to 6.30 pm in our Paris and Antwerp offices.