The Diamond 4С’s are the carat weight, clarity, colour and cut. All of these assessment factors help determine the value of a diamond and compare diamonds with each other.
The 4С’s rule was initially represented in the middle of the XX century, when the world first obtained a universal diamond quality determination tool providing a transparent method for establishing their value.
The diamond assessment considers four factors which are known as the 4 C’s:
One of the most important parameters is a diamond’s colour. It is the first thing which is assessed with the unaided eye and by which the external appearance of a diamond is judged. All diamonds may be divided into two main colour groups - colourless diamonds and fancy-colour diamonds (yellow, light blue, dark blue, red, green, pink and others).
Both the GIA (Gemological Institute of America) system and the Russian GOST R 52913-2008 system can be used to determine the colour.
The colour of a diamond is assessed in accordance with the International Colour-Grading System, from D through M, with D being the most colourless, and M being a most pronounced yellow.
A carat is a measure of weight of gemstones, including, of diamonds. To understand the carat weight of a diamond is, it is necessary to consider it in conjunction with the other two criteria, i.e, the diameter of a diamond measured in millimetres, as well as proportions and symmetry of the diamond cut. For example, when viewed from above, diamonds with a bigger diameter of upper table look larger than the gemstones with a larger carat weight but a lesser surface of the table.
Diamonds are subcategorized into small-, medium- and large-sized:
Diamond weight and size correspondence:
Ct | 0,05 | 0,10 | 0,20 | 0,25 | 0,30 | 0,40 | 0,50 | 0,70 |
Ø mm | 2,5 | 3,0 | 3,8 | 4,1 | 4,5 | 4,8 | 5,2 | 5,8 |
Ct | 0,90 | 1,00 | 1,25 | 1,50 | 1,75 | 2,00 | 2,50 | 3,00 |
Ø mm | 6,3 | 6,5 | 6,9 | 7,4 | 7,8 | 8,2 | 8,8 | 9,4 |
Diamond clarity is a parameter that determines the number of inclusions in a specific gemstone. As the gemstone grows, inclusions and internal flaws may appear that could only be classified on tenfold magnification. Each inclusion emphasizes the individuality and uniqueness of a diamond and is at all times specified in a certificate, which allows to determine the value of the gemstone.
A diamond is considered flawless in the absence of any inclusions, whereas the availability of a number of inclusions have an impact upon the gemstone’s brilliance, as the inclusions prevent light refraction and reflection.
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