To ensure a correct certification of the diamond, there are international rules, which allow an objective evaluation in every part of the world.
Between the 40s and 50s the G.I.A. (Gemological Institute of America) developed the International Diamond Grading System. Thus giving rise to the evaluation system universally known as “4C”, which stands for the initials of the four fundamental parameters for the evaluation of a diamond:
CUT: CUT
COLOR: COLOR
PURITY: CLARITY
WEIGHT: CARAT
Of all the evaluation parameters, the proportion of the cut (cut) is by far the most important.
When the proportions are perfect, all the light received by the stone is reflected from the table or from the facets of the crown, in fact the intent is to evaluate the refractive capacity and the term CUT refers not to the shape of the diamond, but to the quality of the cut .
If the pavilion is too high, or rather shallow, the light passes through the facets of the pavilion itself and is lost without making the stone shine.
The only stones classifiable as cut stones are those from 0.25 carats upwards
The fundamental elements for the evaluation of the cut of a diamond are:
– Table diameter percentage: the proportion of the width of the table with respect to the diameter of the shape of the brilliant cut.
– Crown height percentage: the proportion of the height of the crown with respect to the diameter of the shape of the brilliant cut.
– Pavillon depth percentage: the proportion of the pavilion depth compared to the diameter of the brilliant cut shape.
If it is true that the perfect stone is colorless, it is also true that in nature colored diamonds often appreciated more than white ones thanks to this characteristic, where the color it is so intense that it becomes an asset.
The color of the diamonds is evaluated by illuminating the stone from the north and on white paper in a suitable environment, all this to avoid distortion by light sources.
Coloring is a phenomenon due to the presence (in small percentages) of chemicals that give the stone pleasing yellow, blue, green and pink tones.
The only valid method to determine the exact color of the diamond is to compare it with another that has been classified as a touchstone.
A diamond has formed over 900,000 years.
In such a long period of time inside the crystal there were inevitably incorporated both internal and micro-inclusions stains on both the external surface. The classification of the purity of the gem contributes significantly to determine the value of the gem.
We then evaluate how many imperfections the stone contains and its total characteristics: external and internal. It is evident that in a scale of purities that goes from IF (INTERNAL FLAWLESS) to SI (SMALL INCLUSION), passing through VVS (VERY VERY SMALL) and VS (VERY SMALL). Although it has no influence on the beauty of the gem, it is clear that the purer this is, the higher its value will be.
The weight of precious stones is determined in carats. One carat is 0.20 grams; it takes five stones of 1 ct. to equal the weight of 1 gram. The carat, in turn, is divided into 100 parts: 1 hundredth of a carat equals 1 point.
It seems that the adoption of the carat, as a unit of measurement, dates back to 1200 and is due to Marco Polo, who, in the need to standardize, in the various markets with which he came into contact, a unit of equal weight for all, he used the seeds of the carob tree (carat in Arabic).
The seeds of the carob tree have the characteristic of always having the same weight, whether they are the gigantic carob trees of the savannah or the tiny fruits of the temperate climate areas.
Now we use different methods of course, using electronic microbalances that can measure weight up to five digits after the decimal point.
Monitoring the weight throughout the working process of a diamond is certainly a fundamental safety operation.
In 1970, for the first time, it became necessary to have diamonds that enjoyed an international certification. This in favor of a nascent investment market in diamonds and with a recognition of their value that was universally accepted. In short, shared certification parameters were adopted and the three major International Certification Institutes were established:
– GEMMOLOGICAL INSTITUTE of AMERICA (GIA)
– HOGE RAAD VOOR DIAMANT – ANTWERPEN (HRD)
– INTERNATIONAL GEMMOLOGICAL INSTITUTE – ANTWERPEN (IGI)
Since then, the certificates issued by the aforementioned Institutes fulfill the function of international recognition which, in close connection with the RAPAPORT list, allows an immediate and unambiguous attribution of the value of the diamond throughout the world.
The Kimberley Process is a joint agreement of the governments of the main countries of the world and of the diamond producing multinationals, which guarantees, under the aegis of the UN, that the profits made by the diamond trade will not be used to finance civil wars.
The agreement also obliges the participating countries to strictly control the import and export of rough diamonds.
The Kimberley Process was signed in May 2000, during a conference in Kimberley, South Africa, precisely to try to resolve the problematic link between diamond production and war conflicts.
Is named after the Kimberlite, the rock from which the diamonds are extracted and from the city of Kimberley, where the first deposits were discovered in South Africa.
In 2002, 37 States signed the agreement for the activation of a certification system in the circulation of rough diamonds in Interlaken.
Three requirements that must be met to adhere to the certification scheme are basically:
– Diamonds cannot be used to finance rebel groups or other organizations that aim to overthrow the government recognized by the United Nations.
– Each exported diamond must be accompanied by a certificate proving compliance with the Kimberley Process scheme.
– No diamond can be imported from, or exported to, a country that is not part of the Kimberley Process.
A certificate of origin certifies the entire course of the stones, guarantees their origin and all the steps, from the rough to the cut diamond.
The famous “RAPAPORT”, official list of diamonds, is published weekly in New York and has a global value.
Rapaport prices are expressed in US Dollars. In the Rapaport price list are considered the weight, the color and the purity and not the cut, very important element for the evaluation of the single stone. This price list is therefore to be considered “reference”.
It is the only price list that guarantees a serious listing, free from manipulation, and under the control of Diamond Trading Company.
DTC, in the cartel with the Russian ALROSA, with which it shares the world market of Diamonds, manages the raw material to be supplied to the market, calibrating the quantities according to market demand and ensuring the annual increase in the value of the diamond to make it the most safe and attractive among all forms of investment.