The diamond and the 4Cs
Preciousness
The beauty of its brilliance is due to the fact that it has a high index of refraction of light.
It is the most expensive stone because it takes ten tons of ore to extract just one carat of diamond.
Not all diamonds are used in jewelry.
The slightest defect can detract from their value and they are then used for industrial applications.
These are internal bubbles, foreign particles or inclusions, poor coloring or when they have an irregular shape.
The carat
The mass of a diamond is measured in carats, one carat is equal to 0.20 grams .
The value of a diamond is exponential with respect to its mass.
A two-carat diamond is worth more than two one-carat diamonds, since it is considered rarer .
Its value also depends on its color, its purity...
The 4C rule
It is used to determine the price of a diamond based on a ratio: Cut, Color, Clarity and Carat.
These four qualities make diamond the most famous of precious stones in jewelry.
The beauty of its brilliance is due to the fact that it has a high refractive index. light and high dispersive power
CUT: Size
The degree of beauty of the dispersion (rainbow effect) of the diamond depends, to a large extent, on the cut and polish of the stone.
This diamond grading criterion is the only one that results from the work of the diamond lapidary and the laboratories award a cut grade according to the table below.
Diamond cutting is mainly carried out at Antwerp (Belgium), at Tel Aviv (Israel) and to Gujarat (India) by the community Jain.
Due to its extreme hardness, diamond can only be machined by another diamond , which is why the cut and polish of the stone are the most important elements.
C - Color
Diamonds are also classified by color.
The most common color being “ white ”
(absence of color: that is to say that the diamond is transparent and colorless).
These colors are rated from D (purest white) to Z (darkest shade).
The color grading was established by the independent laboratory GIA
(Gemological Institute of America).
Diamonds of another color such as blue diamonds are called Fancy Colored Diamonds and have a different grading system.
C Clarity: Purity
Diamonds also contain a wide variety of inclusions that can alter their appearance.
An inclusion or impurity in a diamond is nicknamed a toad in France.
Inclusions are indicated using the following codes.
The Carat (weight)
The mass of a diamond is measured in carats, which equals 0.20 grams.
The value of a diamond is exponential to its mass.
In other words, a two-carat diamond is worth more than two one-carat diamonds, since it is considered rarer and therefore more expensive.
Gemological laboratories are responsible for certifying the characteristics of diamonds according to the 4C classification.
This certification involves taking precise measurements of the diamonds, assigning a grade for cut, polish and symmetry, analyzing the fluorescence and assigning a unique number laser-engraved into the diamond. The people responsible for this work are professional gemologists. There are few global gemmological laboratories, the best known are:
Gemological Institute of America (GIA) to new York
High road for diamonds (HRD) to Antwerp ;
International Gemological Institute (IGI) in Antwerp;
GGTL Laboratories, has Geneva and in Liechtenstein;
Fellow of Gemmological Association (FGA) to London ;
American Gem Society (AGS) in New York;
French Gemmology Laboratory (LFG) to Paris .
The diamond cutter (a term originally used to designate a diamond cutter), unlike the gemologist, does not study the diamond but trades in it.
Depending on their specialty, their activity will concern cut stones or rough stones, some combining both.