The ABC's of diamonds

There is an infinite number of things to say - and write - about diamonds! So much so that the diamond has its own ABC. All the letters of the alphabet are used to describe the properties and quality criteria that determine the value of each carbon crystal found in nature.  

Types a and b

You will rarely hear about it, but the diamond classification system starts with the first letters of the alphabet! The diamonds of types a (I and II) and b (I and II) are differentiated by the proportion of certain elements which they contain such as nitrogen, or by the presence of boron. One passes you the course of physics and one passes to C.

4 C

You've probably already heard of the 4Cs. But do you really know what is behind this quartet?

- Carat

In gemology and jewellery, the carat is the unit of measurement of weight. 1 carat corresponds to 0.2 grams. It is not the same thing when we speak about gold, the "carats" (8, 14, 18 or 24 carats) designate the purity of the metal, namely the proportion of gold that there is in the alloy.

- Color

The notion of color is valid for all diamonds...colorless! Yes, it sounds paradoxical when you put it like that. Explanation in the next chapter of the alphabet.

- Clarity (purity)

The purity of a diamond refers to its internal perfection. This criterion of quality makes it possible to describe to what extent the possible impurities and inclusions of a cut stone are visible with the magnifying glass...or with the naked eye. These 'imperfections' can affect the brilliance of the stone, but sometimes they are the source of its charm.

Here is the literate gradation system, from highest purity to lowest:

IF = Internal Flawless (absolutely transparent)

VVS1 - VVS2 = Very very small inclusions (not visible to the naked eye)

VS1 - VS2 = Very small inclusions (nothing visible to the naked eye)

SI 1 - SI2 = Small inclusions (some inclusions can be seen with the naked eye)

I1, I2, I3 = Piqué (inclusions are visible to the naked eye)

- Cut (size)

Cutting stone is the work of the lapidary, and requires an immense know-how. During the cutting process, 50% of the weight of the stone is lost in the best of cases. Every gesture counts and is of great value. Moreover, a badly cut stone, i.e. one that does not respect certain ideal proportions, will shine less. Worse, a mistake in the cut can even create a 'window' in the stone, that is to say a kind of black hole that will completely alter its fire.

D to...Z

As mentioned above, there is a lettered scale to designate the colour of diamonds that are said to be "colourless" or "in the white range". This gradation exists to describe how white a colourless diamond is, knowing that crystal often tends to lean towards yellow. The top 5 are therefore held by the letters D, E, F, G and H.  

The differences in shade between them are almost invisible to the naked eye and must be determined with reference models. The value of the stone decreases as you go through the letters of the alphabet up to Z, and then it goes up again. After Z comes the "Fancy", or flash yellow diamond, a very rare and expensive stone.

A little anecdote: the term "blue-white diamond" that you may have heard in the past is now obsolete, and you should no longer hear it from a real jeweller.