The 4 C – Passion Diamond

The 4 C

The brilliant qualities of the diamond: the 4 C

Each diamond is unique and each reflects the history of its arduous journey from the bowels of the earth to the object of investment or ornament. All diamonds, however, share particular characteristics that allow us to compare and evaluate them and thanks to G.I.A. which, in the early 1950s, developed a measurement system to compare the different qualities: the International Diamond Grading System and the 4 C.


The weight of the diamond, like that of other gems, is measured in carats (ct.) : the standard unit of measurement of the weight.

The term carat comes from the Arabic “qirat”, the twenty-fourth part of a coin, the “dirham”, which in turn derives from the Greek “keration” “carruba”, whose seeds were used to weigh precious.

Popular culture gave the seeds of the carob to be all identical: so what better yardstick to weigh small and precious objects, stones and metals? And, by averaging, currently the weight of the carat, in the decimal metric system, is detected in 0.2 grams.

1 ct plus 0.20 g à 5 ct plus 1 g

In the diamond industry the weight is calculated up to the thousandth of carat and then rounded to the hundreds, commercially called “dot”.

It is important to remember that the price of the diamond, expressed precisely in carats, does not increase in an arithmetic compared to its weight: a 2 ct diamond. it won’t cost twice as much as a 1-ct diamond. equal quality, will cost much more.


The diamond is the only gem in which the absence of color determines its value: the most valuable stones are those totally colorless, commonly called “white”. Colorless diamonds correspond to only a small percentage of those extracted and for this reason their price increases compared to most diamonds, more than 90%, which have shades of yellowish and brown base.

There is also a minimum amount of diamonds, the “fancies”, with more or less intense natural colors: yellow, orange, pink, green, blue or red, which by virtue of their rarity can reach very high prices and are excluded from the normal categories of color and inserted in a special classification.

In the scale invented by G.I.A., letters are used from the alphabet starting from the letter D, which represents the colorless, up to the letter Z.

The quality of the color is determined by the gemologist comparing the diamond with a range of reference stones called “master stones”.


During the crystallization process, small traces of carbon or small crystals of different nature remain imprisoned in the diamond: they are called “inclusions” and are uneven and are considered natural footprints and their number, color, size and position determine the purity of the diamond.

Diamonds considered pure are those observed with a 10-magnifier (10 x) lens, have no inclusion

Thanks to the G.I.A. scale, we can determine the degree of purity and describe the level of inclusions, an eleven-level scale:

  1. IF or LC (internally flawless or loup clean) is pure to the lens, no internal inclusion visible at 10x
  2. VVS 1 (very small) – Usually it is a single inclusion extremely difficult to detect with a 10x lens
  3. VVS 2 (very small) – very small inclusions visible only by an experienced eye with a 10x lens
  4. VS1 (very small) – very slight inclusions that can be detected with a 10x lens
  5. VS2 (very small) – very slight different inclusions in the genre visible with a 10x lens
  6. SI1 (small inclusions) – small inclusions that are easy to detect with a 10x lens
  7. SI2 (small inclusions) – small inclusions that are easy to detect with a 10x lens
  8. YES 3 (small inclusions) – inclusions visible to the naked eye only by an expert
  9. I1 (The Piquè) – inclusions immediately visible with a 10x lens and difficult to detect with the naked eye
  10. I2 (II Piquè) – large and numerous inclusions that decrease its brilliance easily visible to the naked eye
  11. I3 (III Piquè) – large and numerous inclusions, distinctly visible to the naked eye that significantly reduce its brilliance and compromise its structure by making it more fragile

Today, in any part of the world where you buy a diamond, the most commonly used terms, in all languages, are the aforementioned established by G.I.A.


The secret of the beauty of a diamond lies in the interaction between stone and light:

  1. In the way that light meets the surface of the diamond
  2. In the amount of light that enters the diamond
  3. In the manner and form that light performs in the eyes of its observer

When we speak of “brilliance” we refer to that combination of reflections of white light that spring from the surface and from the inside of the diamond.

With the term “fire” instead we refer to those flames of color that emits the diamond.

While the “sparkle” are those flashes of light that are visible when both the diamond and the light source or the observer are in motion.

The most used cut is the “brilliant round” consisting of 57-58 facets, of which 33 on the top (on the crown) and 25 on the bottom (on the pavilion).

The optimal brilliance is achieved when the crown represents a third of the total height of the diamond.

The brilliant round cut is the one that best makes the phenomena of refraction and reflection of light in the diamond stand out and is therefore the most appreciated and requested. It is also worth pointing out that it represents the only cut for the investment diamond.

This of all the 4 C is certainly the most important for the financial diamond: only if the examination of the cut meets the proportions, the symmetry and the finish more refined the diamond will be able to access the certification.

However, there are also other cuts:

Drop and heart
59 veneers

56 veneers

Navette or marquise
58 veneers

76 veneers

48-50 facets

62-70 veneers

The shape and perfection of the cut are of absolute importance in determining the value of the stone. In fact, the value of the diamond is determined in relation to three factors:

  1. Proportions (proportions)
  2. Symmetry
  3. Polish (finish)

The cut classification has four parameters:

  1. EXCELLENT (EX) – perfectly proportioned round diamonds to create the best compromise between fire and brilliance. These diamonds are normally much more expensive as the skill and expertise used to perform this cut allow you to make a higher beauty diamond and to achieve this you need to sacrifice a good part of the original rough diamond.
  2. VERY GOOD (VG)– cut diamonds that reflect the requirements of depth with respect to the board and thanks to these proportions the royal diamond to its observer a maximized brilliance.
  3. GOOD (G) – diamonds cut in an acceptable way but do not have the ideal proportions since their level of brilliance and fire is good and they are excellent stones to create excellent quality jewelry.
  4. FAIR (F) – diamonds that deviate from ideal proportions since the goal was to recover as much weight as possible from the rough stone without taking care of the brilliance and fire. Passion Diamond does not recommend these stones.
  5. POOR (P) – diamonds that look lackluster. Passion Diamond does not recommend these stones
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