The four characteristics that determine the value of diamonds are called “4C’s” and are: Carat (weight or karat), Color, Clarity (purity) and Cut (size) to which a last factor would be added, which would be fluorescence.
Diamonds, unlike other gemstones, follow an official quote based on their weight, color and clarity, which is determined weekly in Antwerp and published on the list called Rapaport. Only professional gemologists and prestigious gemological laboratories can determine exactly the qualities of the diamond, so in the case of diamonds of a certain size it is always advisable to ask for the stone’s certificate. The most prestigious diamond certification laboratories are GIA, HRD and IGI.
1. WEIGHT (CARAT)
The weight of a diamond is measured in carats (1 qt = 0.20 grams), and it is the most determining factor in estimating the price of a diamond. The two key concepts to take into account regarding the price are:
- The price of diamonds increases exponentially with respect to weight, so a one carat diamond is not worth twice as much as a half carat diamond but approximately four times.
- The price of diamonds is determined by blocks, so a 0.49-carat diamond, despite being visually almost identical to a 0.50-carat diamond, will be cheaper, as it belongs to the 0.49-carat price block. carats instead of 0.50 – 0.59 carats.
2. COLOR (COLOR)
The color of a diamond greatly influences its beauty and price. The more colorless, the better quality.
The most widely used color scale today is that of the GIA gemological laboratory, which is the one used in most jewelery stores. This scale orders the color of diamonds in alphabetical order from the letter D (perfect colorless) to Z (yellow or brown).
The dodging between the different scales would be the following:
- Colors D and E – River – Exceptional White
- Color G and F – Top Wesselton – Extra White
- Color H – Wesselton – White
- Colors J and I – Top Crystal – White with slight color
- Colors K and L – Crystal – Light color
- Colors Z – M – Cape, light yellow and yellow – Color
3. PURITY (CLARITY)
Diamonds are formed over thousands of years under enormous pressure and temperature. This process leaves inclusions in diamonds that determine their purity in the diamond. The purer a diamond, the more light it receives and reflects, producing a greater amount of brilliance than lower-clarity diamonds.
The degree of purity of a diamond is determined according to the number, size and position of its external marks and inclusions, using a 10x magnification (10X) magnifying glass, and the most used purity scale, from the GIA gemological laboratory, is divided into 11 Grades ranging from the highest degree of purity (FL or Flawless) to grade I (inclusions visible to the naked eye, also called piqué). The categories would be the following:
- F and IF for completely pure diamonds
- VVS1 and VVS2, which stands for Very, Very Slightly Included for diamonds with almost negligible imperfections
- VS1 and VS2, which stands for Very Slightly Included
- SI1 and SI2, which means Slightly Included
- I1, I2 and I3, for diamonds with inclusions visible to the naked eye, also called piqué or pitted.
From these categories, it is convenient to discard the minced diamonds called I1, I2 and I3 and as for the rest of the categories it will depend on the economic capacity, but logically the purer the better.
4. SIZE (CUT)
The size influences the price in two ways: On the one hand the type of size and on the other the quality of the size.
- Although there are many possible cuts, the most common to get the most out of diamonds is the brilliant cut (the one that everyone imagines when thinking of a diamond), which is also generally the most expensive. Examples of other popular sizes would be princess, oval, heart, esmaralda, pear, or cushion.
- Regarding the quality of the cut, this is a key aspect to have a diamond that shines and it is not always paid enough attention. Diamonds with good symmetry and proportion will always reflect the light better and shine much more. The scale used today includes the following grades: Excellent, Very Good, Good, Fair, and Poor. In general, Excellent and Very Good diamonds are the ones we should buy to have a stone with a good reflection.
Finally, another factor that influences the price of a diamond must be taken into account, although it is not included within the four C’s, which would be the stone’s fluorescence. This property in principle should not affect the value of diamonds, but it is no less true that there are people who do not like their stone to shine in dark neon light situations (nightclubs), so in general stones with fluorescence called “Strong” are worth a little less.
And as a recommendation we would say that to make the purchase of an engagement ring it is important to always request a Gemological certificate as that is what will identify all the diamond characteristics.